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ELEMENTS 


OF 

CHEIISTSY: 

INCLUDING 

A COPIOUS SELECTION OP EXPERIMENTS, 


AND 

MINUTE DIRECTIONS FOR PERFORMING THEM. 

TOGETHER WITH 

NUMEROUS APPLICATIONS TO THE ARTS AND PURPOSES OF LIFE. 

ADAPTED TO 

THE USE OF SCHOOLS AND ACADEMIES. 



' J 

BY ALEXANDER FISHER OLMSTED, A.M. 




NEW YORK: 

PUBLISHED BY ROE LOCKWOOD & SON. 
1854. 


Entered, according to Act of Congress, in the year 1854, by 
LUCIUS D. OLMSTED, 

In the Clerk’s Office of the District Court of Connecticut. 



PRINTED BY 

C. A ALVOKD, 
‘29 & 31 Gold St. 


STEREOTYPED BY 

THOMAS B. SMITH 

216 William St. N. Y. 






PREFACE. 


Although the following work is a compilation, and can hardly 
aspire to the praise of great originality, yet the author ventures to 
hope that it will be found, on examination, to bear a favorable 
comparison with similar works, in perspicuity of style and arrange¬ 
ment, in practical utility, and in adaptation to the wants of young 
learners,—a class for whom it is especially designed. 

The author has studied simplicity in the arrangement, by dis¬ 
tributing the whole subject into three general heads, denominated 
respectively, General Principles and Laws , The Elements and their 
Combinations , and Organic Chemistry. Since most of the pupils 
in our schools have the opportunity of studying appropriate works 
on Natural Philosophy, he has not deemed it necessary or advis¬ 
able to treat here of the mechanical laws of attraction, heat, light, 
electricity, and magnetism, but by confining himself strictly to 
chemical laws and phenomena, he has gained space to treat those 
subjects with the greater freedom and fulness, and to dwell more 
at large on their important applications to the arts and to the phe¬ 
nomena of nature. 

With the hope of rendering the Work more useful to the pupil, 
and more acceptable to the instructor, three articles are added: 
one on Experiments , containing a copious selection adapted to a 
complete illustration of the text; the second on Chemical ProcesseSy 
describing various operations of the laboratory; and a third on 
Chemical Apparatus , in which certain forms of apparatus not men¬ 
tioned in the former parts of the work are described. 

In the preparation of the work, a great number of the most ap¬ 
proved authorities have been consulted, but more especial use has 
been made of the excellent treatises of Fowne & Gmelin. The 
author has also been favored with the advice of his father, Pro¬ 
fessor Olmsted, and has received many valuable suggestions from 
Mr. William J. Craw, of the Yale Analytical Laboratory. 


REVISED EDITION. 


The author had completed the preparation of this revised edi¬ 
tion, and reviewed the proofs as far as the last part, on Organic 
Chemistry, when his health failed, his ardent anticipations were 
suddenly checked, and, after a painful illness, he sunk into the 
grave. Encouraged by the favorable reception which the work 
had met with from instructors and others, he applied himself with 
characteristic zeal and energy to the preparation of a new edition, 
enlarging his acquaintance with the most approved authors in 
every department of the science, devoting himself diligently to the 
practical operations of the laboratory, especially in analytical and 
agricultural chemistry, and finally re-writing, with unwearied 
pains, the greatest part of the work. 

The remaining part, relating to Organic Chemistry, was left by 
the author in a good state of preparation, and it required only 
careful supervision to complete the design; but the shock occa¬ 
sioned to his family by the untimely death of one so justly be¬ 
loved, prevented for some time their giving any attention to the 
subject. At length, they were so fortunate as to secure the aid 
of Mr. William J. Craw, Chemical Assistant in the Analytical 
Laboratory of Yale College, a near friend, and long a fellow-stu¬ 
dent of the author, who has kindly revised the copy and superin¬ 
tended the press, so as to insure to the last part a degree of accu¬ 
racy and finish equal to those given to the former parts which 
passed under the eye of the author himself. Under these circum¬ 
stances, it is confidently believed that few works of the kind will 
be found to present, in so small a compass, so lucid an exposition 
of the great principles and useful facts of the science of Chemistry; 
and the publishers feel assured, that those instructors who ex¬ 
pressed so favorable an opinion of the work at its first appearance, 
will find it in its present improved state more especially deserving 
of their approbation and patronage. 


CONTENTS 


PAGE 

Definitions and General Proper¬ 


ties of Matter. 9 

Chemistry defined. 9 

Organic and Inorganic Chemistry,... 9 


Chemical do. 9 

Analysi#and Synthesis. 10 

Minuteness of Atoms.*. 10 

Matter indestructible. 10 

Attraction. 10 

Repulsion. 11 


IIEAT. 

Leading effects of Heat... 12 

Expansion. 12 

Thermometer. 15 

Pyrometer. 10 

Liquefaction and Congelation. 19 

Vaporization and Evaporation. 22 

Ebullition. 22 

Steam. 26 

Distribution of Heat. 29 

Conduction. 33 

Convection. 34 

Quantity of Heat in Bodies. 36 

Specific Heat. 36 

Temperature. 39 

Sources of Heat. 42 

Solar Heat. 42 

Heat of the interior of the Earth.... 43 

Combustion. 43 

Percussion and Friction. 43 

Chemical Action. 44 


electricity by chemical action. 

Galvanism.T. 48 

Voltaic pile.. 49 

Deflagrator. 50 

Effects of Galvanic Action, in igni¬ 
tion, combustion, and decomposi¬ 
tion . 52 

Electrolyping. 54 

Magnetism by Galvanic Action. 55 

Electric Telegraph... 55 

Galvanic Batteries. 55 


LAWS OF CHEMICAL AFFINITY. 

^principles of Affinity enumerated.... 57 


PAGE 

THE ELEMENTS AND THEIR COM¬ 
BINATIONS. 


Number of elements. 61 

List of elements.. 61 

A tmo sphere .. 62 

Oxygen. ..." 62 

Ozone . 66 

Oxides and Acids. 67 

Nitrogen. 68 

fVater . 69 

Decomposition of Water. 70 

Synthesis of Water. 71 

Hydrogen. 72 

Chemical properties of Water. 76 

Carbon . 77 

Diamond. 77 

Plumbago, Lampblack. 77 

Charcoal. 78 

Symbols explained. 80 

Sulphur . 80 

Silenium . 82 

Phosphorus . 82 

Chlorine . 84 

Iodine . 86 

Bromine . 88 

Fluorine . 89 

Silicon and Boron . 89 


ACID COMPOUNDS AND NON-METAL LIC 
ELEMENTS. 


Classification of these elements. 90 

Sulphurous Acid. 91 

Sulphuric Acid. 92 

Nitrous Acid. 95 

Nitric Acid. 96 

Phosphorous Acid. 98 

Phosphoric Acid. 99 

Carbonic Acid. 99 

Carbonate of Lime. 1U2 

Hydrochloric Acid. 102 

Chlorous Acid. 104 

Chloric Acid. 105 


Hydro-Sulphuric Acid (sulphuretted 
%■ hydrogen). 106 


Hydro-Fluoric Acid. 110 

Silicic Acid. Ill 

Silica. 112 

Fluoride of Silicon. 112 
















































































VI 


C ONTE NTS. 


PAGE 

Tables of Simple Elements and Acid 
Compounds. 115 


NEUTRAL COMPOUNDS OF NON-METALLIC 
ELEMENTS. 

Nitrous Oxide (Protoxide of Nitrogen) 117 


Nitric Oxide. 119 

Carbonic Oxide.. 120 

Light Carburetted Hydrogen (Fire 

Damp). 121 

Combustion and Flame . 122 

Safety Lamp. 120 

Blowpipe. 120 

Oxy-Hydrogen Blowpipe. 120 

Heavy Carburetted Hydrogen. 127 

Olefiant Gas. 127 

Gas Lights. 128 

Coal Gas. 129 

Phosphoretted Hydrogen. 132 

Tables of Neutral Compounds. 134 

Oxygen Compounds. 134 

Hydrogen Compounds. 135 


ALKALINE COMPOUND OF NON-METALLIC 


ELEMENTS. 

Ammonia. 135 

Amidogen.•.. 137 

Endosmose and Exosmose ...... 138 

Diffusion of Gases. 140 

Laws of Combination of Gases by 
volume. 144 


METALLIC ELEMENTS. 


General properties of Metals. 145 

Specific Gravities. 140 

Fusibility. 146 

Metallic Combinations. 147 

Classification of Metals.148 


METALS OF THE ALKALIES. 


Potassium ... 

Hydriate of Potash. 

Carbonate of Potash. 

Bicarbonate of Potash. 

Nitrate of Potash. 

Gunpowder. 

Chlorate of Potash . 

Sodium . 

Hydrate of Soda (Caustic Soda).. .... 
Sulphate of Soda (Glauber's Salts).... 

Manufacture of Glass. 

Soda-water. 

Bicarbonate of Soda. 

Chloride of Sodium (Salt). 

Nitrate of Soda. 

Ammonium . 

Carbonate of Ammonia. 

Chloride of Ammonium. 

Sulphide of Ammonium. 

Nitrate of Ammonia. 


149 

150 

151 

152 

153 

154 

155 

156 

157 

158 

159 
161 
162 
162 



165 


166 


167 

167 


PAGE 

METALS OF THE ALKALINE EARTHS. 


Barium .168 

Baryta. 168 

Sulphate of Baryta. 168 

Strontium . 169 

Strontia (Protoxide of Strontium)... 169 

Nitrate of Strontia. 169 

Calcium . 170 

Lime (Protoxide of Calcium). 170 

Mortar.. 171 

Lime in Agriculture. 171 

Use of Lime in the Drummond Light 172 

Chloride of Calcium. 172 

Sulphate of Lime (Gypsum). 173 

Carbonate of Lime. 174 

Marl.. 174 

Lithographic Stones.^- 174 

Fluor Spar (Fluoride of Calcium)- 174 

Chloride of Lime. 175 

Bleaching—Disinfecting. 175 

Phosphate of Lime. 175 

Magn esium . 176 

Magnesia (Calcined). 176 

Sulphate of Magnesia (Epsom Salte). 177 

Carbonate of Magnesia. 177 

Aluminum . 178 

Alumina. 178 

Clay. 179 

Pottery—Stoneware—Earthenware.. 181 

Sulphate of Alumina. 182 

Alum. 182 

Chromium . 183 

Chromic Acid. 183 

Chromate of Potash. 183 

Bichromate of Potash. 183 

Chromate of Lead.. 184 

Mring an . . 185 

Peroxide of Manganese. 185 

Magnanic Acid.. 185 

Iron . 186 

Reduction from its ores. 186 

Properties of Iron. 188 

Protoxide of Iron. 180 

Sesqui Oxide. 189 

Magnetic Oxide. 189 

Proto-sulphuret... 190 

Proto-sulphate (Copperas). 190 

Steel. 190 

Zinc . 193 

Salts of Zinc. 194 

Nickel .:. 195 

Cobalt . .95 

Protoxide of Cobalt. 195 

Chloride of Cobalt. J 96 

Bismuth . 196 

Alloys of Bismuth. 197 

Copper .197 

Bell-metal.. IS 8 

Chinese gong metal.*.. 198 

Brass. 198 

Pinchbeck. 198 

Protoxide of Copper. 199 

Sub-oxide. 19J 

Sulphate (blue Vitriol). 199 

Nitrate. 199 

Bead ... 200 

Sulphuret (Galena). 200 

Protoxide. 201 

Red Lead. 204* 















































































































CONTENTS 


Vll 


PAGE 

White Lead.201 

Mercury . 203 

Protoxide.204 

Sub-cldoride (Calomel).-. 204 

Perchloride (Corrosive Sublimate)... 204 

Sulphuret. 205 

Alloys of Mercury. 206 

Silver . 207 

Chloride. 208 

Process of Cupellation.208 

Nitrate. 210 

Indelible Ink.'. 210 

D.iguerreotype plates.211 

Arbor Dianas. 212 

Fulminating Silver. 212 

Tin . 213 

Tinplate.*.. 214 

Speculum-metal. 215 

Antimony .. 215 

Type-metal.216 

White-metal. 216 

Sulphuret.216 

Arsenic . 217 

Arsenious Acid. 217 

Arsenic Acid. 219 

Sulphuret./. 219 

Gold . 219 

Fulminating Gold.222 

Platinum . 223 

Platinum sponge. 224 

Platinum black. 224 

Bichloride of Platinum.225 


ORGANIC CHEMISTRY. 

Chemical peculiarities of organized 


bodies. 228 

Vegetable Chemistry . 232 

Origin of Plants. 232 

Germination.233 

Seeds and Leaves. 234 

Non-azotized bodies. 235 

Starch. 235 

Sago. 236 

Dextrine and Grape Sugar.237 

Sugar . 237 

Sugar of Grapes. 237 

Sugar of Cane. 239 

Sugar of Milk. 239 

Lactic Acid. 240 

Gum . 240 

Gum Arabic..*..240 

Pectine and Pectic Acid.241 

Cellulose—Vegetable Tissue. 241 

Gun Cotton—Pyroxiline. 243 

Collodion. 243 

Organic Acids .244 

Oxalic Acid.244 

Tartaric Acid.245 

Cream of Tartar. 246 

Tartrate of Antimony. 247 

Pyroligneous Acid...247 

Acetic Acid. 248 

Acetate of Lead. 249 

Verdigris. 249 

Citric Acid. 249 

Malic Acid. 250 


PAGE 

Tannic Acid. 250 

Gallic Acid.250 

Fermentation .. . i.252 

Saccharine fermentation. 252 

Sugar refining.254 

Vinus fermentation. 255 

Bread making.256 

Yeast.256 

Alcohol. . . 258 

Rum. 259 

Gin. 260 

Cider. 260 

Ether.. 260 

Wood Vinegar (Pyroligneous Acid).. 261 

Chloroform. 262 

Wood-tar. . . 263 

Origin of Soils . 263 

Humus. 264 

Oils and Fats . 266 

Margarine. 267 

Stearine. 267 

Margaric and Oleic Acids. 267 

Butyrine and Butyric Acid. 269 

Glycerine. 269 

Wax.*.270 


Cetine (Spermaceti). 

Linseed Oil. 

Volatile Oils . 

Oil of Turpentine. 

Oil of Bitter Almonds. 

Oil of Cinnamon. 

Camphor. 

Oil of Black Mustard. 

Resins and Balsams. 

White Resin. 

Resin Soap.. 

Resin Oil. 

Lac. 

Caoutchouc (Indian Rubber).... 

Gutta-Percha. 

Azotized Principles . 

Cyanogen. 

Hydrocyanic Acid (Prussic Acid) 

Cyanide of Potassium. 

Cyanide of Mercury. 

Cyanic Acid. 

Cyanite of Ammonia. 

Ferrocyanide of Potassium. 

Ferrocyanide of Iron. 

Sulphocyanide of Potassium. 

Fulminic Acid. 

Fulminate of Silver. 

Fulminate of Mercury. 

Vegetable Alkalies . 

Morphia. 

Narcotine. 

Cinchonia. 

Quinine. 

Sulphate of Quinine. 

Strychnia. 

Caffeine. 

Nicotine.. 

Artificial Alkaloids. 

Organic Coloring Principles .... 

Art of Dyeing. 

Chlorophyl. 

Indigo. 

Litmus. 

Cochineal. 


270 

271 

272 

274 

275 

276 

276 

277 
277 
277 
277 

277 

278 

278 

279 
281 
281 
281 
282 
282 
283 
283 

283 

284 
284 
284 

284 

285 

286 
286 
286 
287 
287 
287 

287 

288 
288 
289 

289 

290 

290 

291 

292 

293 






































































































































vm 


C ONTENTS 


Madder.. 

Animal Chemistry. 

Chemical peculiarities of Animals.. 
Constituents of Animal Substances . 

Fibrine.. 

Albumen. 

Casseine. 

Gelatine... 

Blood... 

Respiration.... 

Skin.. 

Milk. 

Fat. 

Bones.. 


PAGE 

Relations of Chemistry to Common 
Life . 308 

EXPERIMENTS. 

List of Experiments, with minute 
directions for performing them.... 310 

CHEMICAL PROCESSES. 

Minute directions for fitting and ar¬ 


ranging Chemical Apparatus. 349 

CHEMICAL APPARATUS. 

List of articles required for Chemical 
Experiments...353 


PAGE 

. 293 

. 293 

. 294 

. 296 

. 296 

. 297 

. 297 

. 299 

. 300 

. 303 

. 304 

. 305 

. 307 

. 307 


















ELEMENTS OF CHEMISTRY 




PART I. 

GENERAL PRINCIPLES AND LAWS. 

DEFINITIONS AND GENERAL PROPERTIES OF MATTER 

1. Chemistry is that science which has for its object, to 
investigate the composition of bodies, and the changes of con¬ 
stitution which they produce by their action on each other. 

Natural philosophy respects masses; chemistry, particles 
of matter. 

Air, earth, and water, when considered with reference to 
their constituent elements, belong to chemistry; when in re¬ 
lation to the vast masses of the atmosphere, the land, and the 
ocean, they come under natural philosophy. 

2. Chemistry is divided into organic and inorganic , corre¬ 
sponding to the two great departments of nature—the living 
and the inanimate. Organic chemistry investigates the com¬ 
position of bodies possessing life , and tJie changes produced in 
these bodies by other substances. Inorganic chemistry pertains 
to inanimate nature, and includes the composition and mutual 
agencies of bodies not organic. 

3 The properties of matter are -chemical or mechanical. 
The chemical properties are those ivhich produce a change in 
the constitution or nature of bodies; the mechanical, those 
whicli alter the figure , position , or properties of bodies with¬ 
out a change in their constitution. The extraction of the 
juice of apples by pressure, is mechanical ; but the spontane- 


1. How is Chemistry defined? How are Natural Philosophy and Chemistry 
distinguished ? 

2. Into what parts is Chemistry divided ? What is the object of organic 
Chemistry ? What is the province of inorganic Chemistry ? 

3. How are the mechanical and chemical properties of matter distinguished ? 
In making cider, what part of the process is mechanical ? What is chemical ? 
What part of the process of making bread is mechanical ? What is chemical ? 
In what respect are the properties oi glass changed by rubbing ? 

1* 





10 


ELEMENTS OF CHEMISTRY. 


ous change which the juice undergoes by fermentation, is chem¬ 
ical. The mixing of flour, yeast, and water, is a mechanical 
operation ; hut these ingredients pass through a chemical pro¬ 
cess when they ferment, and are converted into bread. When 
we rub a glass tube with a piece of cloth, the glass acquires 
the property of attracting light bodies without any change in 
its constitution. 

4. Analysis and synthesis are two methods of inquiry into 
the constitution of bodies. Analysis is derived from a Greek 
word, which signifies “ to resolve,” and denotes the resolution 
of a body into its component parts. It is that method in chem¬ 
istry by which the elements of a body are discovered by resolv¬ 
ing it into its component parts. Synthesis is the opposite of 
analysis. It is derived from a Greek word, signifying “ to put 
together.” It is that method in chemistry by which the con¬ 
stitution of a body is determined by uniting its components. 

5. In entering upon the study of chemistry, it is necessary 
to understand the following properties of matter : 

(1.) All matter is made up of a vast number of extremely 
minute particles, called molecules, or atoms. The particles of 
one grain of copperas, (sulphate of iron,) dissolved and diffused 
in twenty-four million grains of water, will still be easily de¬ 
tected by the proper chemical test.* 

(2.) Matter is indestructible. The elements of which 
bodies are composed, are continually changing their forms and 
modes of combination; but in all these changes of form, they 
still remain unchanged in their nature and properties. Fire 
consumes wood, and the wood appears to be destroyed ; 
but from its combustion other plants derive new life, imbib¬ 
ing through their leaves, or the soil, most of that which es¬ 
capes in smoke or remains behind in ashes. Ice is changed 
into water, and water into steam, by heat; but in the form 
of clouds and rain, of dew, snow, and hail, watery vapor is 
returned again to the earth. Ceaseless change, with a final 
restoration of every particle of matter, attends all the phenom¬ 
ena of nature. 

(3.) Attraction is a tendency of different portions of matter 
towards each other. It may exist between masses or parti- 

* Ferrocyanide of potassium. 


4. What is analysis ? What is synthesis ? 

5. Of what is all matter made up 1 Is any portion of matter destroyed or 
lost ? Does fire destroy, or only change the form of matter ? What becomes 
of smoke and ashes ? Is water lost when converted into vapor ? How does it 
return again to the earth ? What is attraction ? How is gravitation distin- 



GENERAL PRINCIPLES AND LAWS. 


11 


cles. The attraction between masses is called gravitation, 
and the consideration of it belongs to natural philosophy; 
that between particles belongs to chemistry, and includes ag¬ 
gregation^ affinity , and cohesion. Aggregation unites parti¬ 
cles of the same kind in one body, as the particles of lead in a 
musket ball. Affinity unites different particles in one body, 
as particles of copper and zinc to form brass. Cohesion unites 
particles mechanically , and may be overcome by mechanical 
means, as that of a lump of sugar by grinding. The attrac¬ 
tion of gravitation acts at all distances , as when a ball falls 
towards the earth, or when the sun attracts one of the plan¬ 
ets. The several kinds of attraction which exist between 
the particles of matter, act only at insensible distances, as the 
force which binds together particles of gold by aggregation, or 
particles of copper and tin in bell-metal by affinity, or grains of 
sandstone by cohesion. * 

(4.) Repulsion is opposed to attraction in all its forms. 
Attraction binds together the particles of matter; repulsion 
causes them to separate more widely. In solids, attraction 
prevails; in liquids, attraction and repulsion are nearly in 
equilibrium ; and in gases, (or bodies in the form of air,) repul¬ 
sion entirely overcomes the force of attraction. These effects 
generally depend upon heat. At a low temperature, attraction 
prevails ; probably all bodies assume the solid state at a low 
temperature. At a higher degree of heat, repulsion neutral¬ 
izes and finally destroys cohesion, and all bodies assume the 
gaseous state. Thus, zinc at common temperature is solid, the 
particles being firmly united by cohesion ; at a higher temper¬ 
ature it melts, and at a very high temperature it is volatilized, 
or driven off in vapor or gas. Mechanical pressure , like at¬ 
traction, opposes repulsion. If metallic arsenic be heated 
without pressure, it will rise at once in vapor without melt¬ 
ing ; but if it be heated under great pressure, it will be 
obtained in the melted state. 


guished from aggregation, affinity, and cohesion? What is said of aggrega¬ 
tion ? What force unites copper and zinc to form brass ? What is said of co¬ 
hesion ? By what force does a body fall to the earth, or a planet revolve around 
the son ? At what distance does gravitation act ? How are the attractions of 
aggregation, affinity, and cohesion defined ? To what is the force of repulsion 
opposed ? What is the action of these two forces on the particles of matter / 
Does repulsion or attraction prevail in solids? In liquids, what >si the state of 
these two forces ? Which prevails in gases ? On what do these forces gener¬ 
ally depend ? Does attraction prevail at a high or low temperature / A t winch 
temperature does repulsion prevail ? How is the solid state of zinc explained . 
Why is zinc melted ? Why is it driven off in vapor at a high temperature / 
What is said of mechanical pressure ? 




12 


ELEMENTS OF CHEMISTRY. 


OF HEAT. 

6. The cause of the phenomena of heat is unknown, but it 
is supposed to he a highly attenuated, imponderable substance, 
the particles of which repel each other, but are attracted by 
other substances. To this substance the name caloric is given. 
It will be convenient to consider the phenomena of heat under 
the following heads : 1. Its effects ; 2. Its distribution ; 3. Its 
quantity; 4. Its sources. 

7. The leading effects of heat are, to enlarge the dimensions 
of bodies, and to reduce solids to liquids and liquids to gases. 
These effects are designated by the terms expansion, liquefac¬ 
tion, evaporation, and vaporization. The withdrawal of 
heat reduces gases to liquids and liquids to solids ; the first is 
called condensation, and the second congelation. 

, EXPANSION. 

8. All bodies, whether solid, liquid, or aeriform, are ex¬ 
panded by heat and contracted by cold. In solids, the degree 
of expansion is usually small, and differs much in different 
bodies, but is greatest in the metals. Liquids expand by heat 
much more than solids. They differ, however, from each other 
in the power of expansion, and even the same liquid is not ex¬ 
panded equally at different degrees of temperature, being more 
expanded at a high than at a low temperature by equal addi¬ 
tions of heat. Thus 10 3 added to alcohol when hot, 
will expand it much more than the same number of 
degrees applied to it when cold. Those liquids vary 
most at different temperatures, whose boiling points 
are the lowest. Gases expand much more than either 
solids or liquids. The great expansion of air by heat 
may be shown by filling a small vial, (Fig. 1,) about 
half full of water, colored with cochineal or carmine. 
Through the cork a tube passes nearly to the bottom 

of the vial. If the hand be applied to the top of the vial, the 
air within will be expanded and drive the liquid up the tube 
and out of the top. It will be necessary to cement the cork so 


Fig. l. 



6. What is supposed to be the cause of heat ? What name is given to this 
substance ? Under what four heads are the phenomena of heat arranged ? 

7. What are the leading effects of heat ? 

8. State the principle of expansion by heat. Are solids, liquids, or gases ex¬ 
panded most by heat 1 Among solids, what bodies expand the most ? Are 
different liquids expanded equally ? Will the same amount of heat added to a 
liquid always raise its temperature in the same degree ? What is said of alco¬ 
hol? Which liquids vary most at different temperatures ? Explain Fig. 1. 




GENERAL PRINCIPLES AND LAWS. 


13 


as to be air tight. The expansion of substances by heat is a 
principle of great value and of frequent application. In put¬ 
ting tire upon wheels, blacksmiths make the iron rim a little 
smaller than the wheel, and then heat it red hot. This en¬ 
larges the rim to such a degree that it will readily encompass 
the wheel. When this has been applied to the wheel, it is 
suddenly cooled, and by its contraction binds the work very 
firmly together. 

9. A very useful application of expansion by heat, is in 
cutting glass by a hot iron, as is constantly practised in the 
laboratory. The glass to be cut is marked with ink in the 
desired direction, and then a crack, commenced by any con¬ 
venient method, at some distance from the desired line of 
fracture, may be led by the point of a heated rod along this 
line with the greatest precision. If the neck of a bottle be 
turned around in a red-hot iron rod, and then 
suddenly dipped in water up to the heated line, it 
will be instantly taken off as smooth and true as if 
it were cut by a diamond. By bending the rod to fit 
different parts of the bottle, or a tube , it may be 
cut off at any required place. In this case the 
glass, being thiclt , cracks by the sudden and un¬ 
equal contraction of the outside and the inside. 

Sometimes, when the iron is very hot, the glass cracks without 
the application of water, by the sudden and unequal expan¬ 
sion of the two sides. If glass is very thin it is almost impos¬ 
sible to crack it by heat; hence, glass vessels for chemical 
purposes are made thin, to bear sudden changes of tempera¬ 
ture. The thinnest glass may, however, be readily cracked 
by fusing upon it a small piece or bead of glass, so as to make 
it thick in the places where it is desirable to start the crack. 
This may be done by applying moisture while the glass is 
still hot, or a heated iron after it has cooled. The crack, thus 
started, may be led in any direction by a red-hot iron. White 
glass bottles answer better for this experiment than the thicker 
dark colored. Hard rocks are sometimes broken in the same 
maimer. A fire is kindled on the rock sufficient to render it 
nearly or quite red hot. Cold water is then suddenly dashed 
on, and the rock splits into numerous fragments, which are 
easily removed by wedges. 

10. In warm weather the rod of the pendulum is lengthened, 
and the clock goes too slow ; in cold weather it is shortened, 


Fig. 2. 



I 


How is the principle of expansion by heat applied in putting tii*e on wheels 7 
In cutting glass 7 

9. Explain Fig. 2. How are hard rocks sometimes broken 7 







14 


ELEMENTS OF CHEMISTRY. 



Fig. 4. 


and the clock goes too fast. To remedy this 
irregularity in the movement of a clock, a pen¬ 
dulum has been contrived, which is called, from 
its form, th q gridiron pendulum. (Fig. 3.) The 
shaded bars, i, i, e , are made of iron ; the light 
bars, b,b, of brass. During the heat of summer 
the bars i, i, will expand a certain length, as 
to the line a; but the same time the bars, b, b, 
will expand upwards more than i, i, expand 
downwards, because brass expands more than 
iron. The pendulum, p , would therefore be 
elevated instead of lowered by these two ex¬ 
pansions. But the bar, e, also expands down¬ 
wards, and therefore lowers the pendulum, p, 
to the proper distance from its point of suspen- 
i sion. By adjusting the length of the bars, i, i, e, 
and b, b, to each other, it is evident that the 
compensation pendulum will keep nearly the 
same time at all temperatures. 

A still simpler compensation pendulum is thus 
constructed. The weight, p, instead of a metallic 
disk, consists of a cylindrical glass jar, (Fig. 4,) con¬ 
taining mercury. This glass 'jar is held in the ex¬ 
tremity of the steel pendulum rod, s, s, s, called the 
“ stirrup.” The same increase of temperature which 
will cause the rod, r, to descend, and become longer, 
will also cause the mercury to rise, so that the centre 
of motion of the pendulum shall be at the same dis¬ 
tance from the point of suspension. 

When different metals are united together, as a 
strip of iron to a strip of brass, (Fig. 5,) and exposed 
to heat, their different degrees of expansion will 
cause the compound bar to assume a curved figure 
If three strips of metal, as copper, zinc, and tin, be 
riveted only at their extremities, the tin being be- 


Fig. 5. 



tween the other two met¬ 
als, they will be bent into 
a curve on each side of 
the strip of tin. 

11. A similar arrange¬ 
ment is applied in the con¬ 
struction of the balance- 


10. What evil is the gridiron pendulum designed to remedy ? Explain its 
construction from Fig. 3. How is the mercurial pendulum constructed ? 

11. Explain Fig. 5. How is the balance wheel of a watch constructed ? 































GENERAL PRINCIPLES AND LAWS. 


15 



wheel of a watch, (Fig. 6.) Every in- Fig. 6. 

crease of temperature must increase the 
diameter of the wheel, and consequently 
greatly affect its rate of going. To ob¬ 
viate this, the circumference of the bal¬ 
ance-wheel is made of two metals, the 
most expansible being on the outside. 

The compound rim is also cut through in 
two or more places, as represented in the 
figure. The effect of this arrangement is, that when the tem¬ 
perature of the wheel is increased, the rim bends inwards, as 
in the first part of Fig. 5, towards, the centre , thus compensat¬ 
ing the expansion of the diameter which would carry it from 
the centre. The centre of gravity of the rim, therefore, re¬ 
mains at the same distance from the centre of the wheel, 
which is essential to its uniform motion. 

12. By the expansion of heat, the thermometer indicates 
changes of temperature. This instrument consists of a gl&ss 
tube (Fig. 7,) with a hollow ball, a , called the bulb, and a 
graduated scale, d. The bulb and part of the tube are filled 
with quicksilver, which by its expansions and contractions in¬ 
dicates the changes of temperature. To measure 
them, the scale, d , is* divided into equal parts, called Fig. 7. 
degrees, and applied to the tube. The thermometer 
commonly used in this country is called Fahrenheit’s, 
from the fact that it was first constructed by Fahren¬ 
heit, a citizen of Amsterdam. Fahrenheit thought 
that by mixing snow and salt he had obtained the 
point of absolute cold. He therefore called this 
point zero, or 0. He then plunged his thermometer 
into freezing water, and marked the place on the ther¬ 
mometer tube where the mercury stood. Having 
marked this point, he now plunged his thermometer 
into boiling water, and marked the height of the mer¬ 
cury. From these three points, the temperature of 
the mixture of snow and salt, that of freezing vrater, 
and that of boiling water, he determined all the divi¬ 
sions of the scale. From boiling to freezing water, 
he made 180 small divisions, or degrees, and continu- 
ing the same scale below the freezing point, he made 


12. What is the object of a thermometer ? Describe this instrument. By 
whom was the common thermometer first constructed ? What process did 
Fahrenheit pursue? At what point did his thermometer commence? How 
many degrees are reckoned from zero to the freezing point of water ? How 
many to the boiling point ? 













16 


ELEMENTS OF CHEMISTRY. 


32 degrees to zero. From zero, therefore, there are 32° to the 
freezing point, and from the melting point of ice to the boil¬ 
ing point of water, there are 180° more, or 212° in all, from 
zero to. the boiling point. 

13. The self-registering thermometer (Fig. 8,) is formed by 
two thermometers of different construction. A is a thermom- 


Fig. 8. 


1 1 1 1 1 \ 

M M M 1 

1 1 ill l 1 1 1 l l l 1 1 1 M : 1 1 Irj ' 1 T~1 

1 Yi 

A 

III w ^ 

t -R— 

B 

Ip 

^ 1 1 H 1 1 

1, Li 'Ml 

! ’■ 1 1 1 1 M 1 1 1 1 1 II 1 II 1 M M 1 l 1 1 


eter partly filled with mercury. At the top of the mercury, 
m , is a small piece of steel wire, w. When the mercury in 
the thermometer expands, it pushes the wire before it. When 
it again contracts, it leaves the wire on the side of the tube, 
and thus the position of the wire in the thermometer, as at iv , 
shows the greatest height to which the mercury has risen. 
This instrument is used to determine the extreme heat 
during the night, or other times during the absence of the 
observer. 

To ascertain the greatest cold , another thermometer, B, is 
placed on the same stand. This thermometer is partly filled 
with spirits of wine. It contains a cylinder of porcelain, which 
adheres to the spirits of wine as it contracts, and is thus 
drawn back to the lowest point of cold. When the fluid ex¬ 
pands again, it passes readily through the cylinder of porcelain, 
leaving it on the side of the tube at the lowest point of con¬ 
traction. The porcelain is restored to its position for a new 
observation, by inverting the thermometer, and the iron cylin¬ 
der is drawn into its place by a magnet. 

14. To determine temperatures above a red heat, an instru¬ 
ment called Daniel’s 'pyrometer , is employed. In this in¬ 
strument a bar of iron, or platinum, is so arranged, that 
its expansions or contractions are registered, and thus very 
high temperatures may be determined. It has been shown 


13. What is the instrument represented in Fig. 8 called ? What is its con¬ 
struction ? 

14. What instrument is used to determine very high temperatures ? How are 
high temperatures indicated by this instrument ? At what temperature does 
brass melt?—copper?—gold ?—cast iron ? 











GENERAL PRINCIPLES AND LAWS. 


17 


that brass melts at 1869°, copper at 
1996°, gold at 2000°, and cast iron at 
2786°. 

15. A metallic ball, a, (Fig. 9,) pro¬ 
vided with a ring, 5, a little larger than 
itself, will, when heated by a lamp, he 
supported by the ring, hut when the 
lamp is withdrawn, gradually cooling, , 
it will contract until it falls through the t 
ring. 

In fig. 10, a bar of metal, a, is 
provided with a handle, and fits into 
a gauge, b, and also passes through 
the hole in c. When .the bar is 
heated, it expands lengthwise, and 
therefore will not enter the gauge, 
b, as at first; it also expands in di¬ 
ameter, and therefore it will no longer 
pass through c. If, on the other hand, 
it is cooled with ice or snow, it will 
not fill the gauge, and it will pass 
loosely through c. 

16. The law that bodies expand by heat and contract by 
cold, is not universally true. The most remarkable exception 
is in the case of water. A large thermometer tube, or bulbed 
glass, filled with water and placed in a cold situation, will 
show a contraction in the column of water, until it has reached 
a cold of 39 D , when the contrary effect will take place. From 
39 2 to 32° the water will expand, and at 32°, in freezing, a 
sudden expansion will take place, so great as often to break 
the bulb of the glass tube in which the water is contained. 

The exception in the case of water to the general law of 
expansion and contraction, was dictated by a benevolence 
which is ever working out the highest welfare and happiness 
of creation. All laws appear to be subordinate to a main de¬ 
sign—the greatest good. So far as these laws carry out this 
design, they prevail; and when in particular circumstances 
they fail in this respect, they give way to exceptions, or laws 
of a more limited character. These principles are beautifully 


15. Explain Fig. 9. (The explanation of every figure should consist of two 
parts: first, the design; secondly, the description. No explanation can be 
perfect where either of these is omitted.) What is the object and description 
of Fig. 10 ? 

16. What remarkable exception is there to the law. that bodies expand by 
heat and contract by cold ? By what experiment may this be illustrated ? 
What appears to be the main design of creation ? Are not general laws essen- 


Fig. 10. 





Fig. 9. 
















18 


ELEMENTS OF CHEMISTRY. 


illustrated in the case of water. In the present arrangement, 
on account of the expansion of water in freezing, ice is lighter 
than water, and therefore floats on its surface. But were water 
to contract in freezing, ice would be heavier than water and 
would sink. In this case, the coating which now protects our 
rivers and streams from the extreme cold of winter, would he 
itself covered, and effectually guarded on the return of Spring 
against its warmth and that of the ensuing summer. In the 
next winter this deposit of ice would he increased, and this 
process, in successive winters, would eventually fill our rivers 
and streams with ice, destroying all the animals with which 
they are now filled, and blocking up navigation. 

There are many liquids besides water, which expand be¬ 
fore assuming the solid form. Several melted metals exhibit 
the same phenomenon, and advantage is taken of this fact in 
the arts. The alloy of which printers’ types or stereotype 
plates are formed, expands as it solidifies, and hence forces 
itself into every part of the mould, and copies it perfectly ; the 
same is the case with melted iron. From such a metal as 
lead, *vhich contracts as it cools, it would be impossible to ob¬ 
tain good castings. 

Clay contracts by heat. It is one of the most important 
points in pottery-ware to calculate the amount of this contrac¬ 
tion in order to preserve the elegance and regularity of the 
vessels manufactured. 

17. The expansion of vapors and 
gases is the same for an equal degree of 
heat. Not only the amount, but the 
rate of expansion, is uniform for all de¬ 
grees of heat. This rate is equal to 
of the volume of the gas at zero, for each 
degree of the thermometer. The expan¬ 
sion of air by heat is one cause of 
winds and atmospheric currents. Bal¬ 
loons are sometimes made to ascend by 
the expansion of air within them, and 


tial to this design? Are these laws without exceptions? Are the exceptions 
equally evincive of benevolence? Why is water near the freezing point an 
exception to the general law that bodies contract by cold ? Are there any other 
liquids besides water that expand on assuming the solid form ? What solids 
exhibit the same phenomenon ? What use is made of this property of certain 
metals in the arts? Why is it not possible to obtain good castings from 
lead? 

17. What is the law of expansion in gases and vapors ? What effects are 
roduced by the expansion of air by heat? Why do balloons, containing 
eated air, rise ? Explain Fig. 11. 


Fig. 11. 





GENERAL PRINCIPLES AND LAWS. 


19 


their consequently increased levity. A balloon made of tissue 
paper, or silk, (Fig. 11,) is filled with heated air, which rises 
through an aperture in the lower part. The heat is produced 
by the flame of a sponge soaked in alcohol, which is suspended 
from beneath, and the air within the balloon becoming in this 
way rarefied, causes the whole to ascend, on the same princi¬ 
ple that a cork rises in water. 

CHANGES OF STATE.-LIQUEFACTION AND CONGELATION. 

18. Solids are converted to liquids, and liquids to vapors, or 
gases, by the addition of heat; the opposite phenomena of 
condensation and congelation take place with the withdrawal 
of heat. Fusibility, or liquefaction, is a property of all solid 
bodies, although some are much more fusible than others. 
Lead and wax are easily melted, but lime and rock-crystal 
cannot be melted by the highest furnace heat. These sub¬ 
stances may, however, be fused by the intense heat of galvan¬ 
ism, or by the oxy-hydrogen blowpipe. 

19. The following are some of the most important facts 
connected with the liquefaction of bodies ? 

(1.) While a solid is melting, its temperature does not in¬ 
crease. Thus, if ice be placed oVfer a fire, it will rise to a 
temperature of 32°, and will remain there until every part of 
it is melted. The same is true of every solid. All heat added 
to a body in this state, appears to be lost, as it does not raise 
its temperature. This, therefore, is called latent heat , or that 
portion of heat which disappears in bodies while they are 
cha?iging their state from solids to liquids , or from liquids 
to vapors or gases. 

The quantity of heat which disappears in ice in changing 
its form to water, is 140°. This maybe proved in the follow¬ 
ing manner : Take two tumblers, one containing a pound of 
ice at 32°, or the freezing point, and the other a pound of 
water at 172°. Pour the water from the second tumbler into 
the first. If no heat disappeared, the mixture would be at 
102°, or midway between 172° and 32°. But in fact, the 
water poured in from the second tumbler has lost all its heat, 
and the mingled water of both tumblers has the temperature 
of that of the first, or the mixture stands at 32°. And still a 
change has been produced in the first tumbler, though not in 


18. What is said of the fusibility of bodies ? 

19. What is the first important fact connected with the liquefaction of bodies ? 
How is latent heat defined 1 How much heat disappears in ice in changing it 
to water ? What is the first method by which this is proved ?—the second ? 



20 


ELEMENTS OF CHEMISTRY. 


temperature, yet in form , for its ice has become water. ^ The 
change of the water of the second tumbler is in temperature , 
being cooled down from 172° to 32°, having lost 140° of 
heat. This may be illustrated in numbers in the following 
way : 

I .—Mixture of two portions of Water. 


MIXTURE. 

1 lb. of water at 32' 

1 lb. of water at 172° 

The result is a mean temperature. 


>.°) 


2 lbs. water at 102°. 


II.— Mixture of Ice and Water. 


MIXTURE. 

1 lb. of ice at 32°. ( a ) 
1 lb. of water at 172° 



RESULT. 

= 2 lbs. water at 32°. 


The result is the reduction of the temperature of the water 
to that of the ice, while the latter undergoes no change in tem¬ 
perature, but merely in its form, being melted or converted to 
water. In this experiment, therefore, 140° (the difference 
between ( b ) 172^ and ( a ) 32°) have disappeared, while the ice 
is converted to water. 

20. Again, let there be a uniform cause of heat, as a 
brightly burning fire, which shall raise the temperature of a 
pound of water placed over it 10° per minute. Starting with 
water at 32°, in 14 minutes this will have a temperature 
of 172° ; but with the same quantity of ice in the same time, 
the temperature will still be 32°, and no apparent effect will 
be produced by the*fire besides melting the ice. From these 
experiments it is evident that 140° of heat disappear in chang¬ 
ing ice to the liquid state. This is therefore the amount of 
latent heat in water. 

21. The latent heat absorbed while bodies are converted, 
from the solid to the liquid state, renders liquefaction cool¬ 
ing process. When ice melts in contact with other bodies, it 
withdraws heat from those bodies. Thus, when placed in a 
tumbler of water, it reduces the temperature of the water, 
and this abstracts heat from the tumbler, and the whole be¬ 
comes cold. A small piece of ice will thus cool a large por¬ 
tion of water, though it floats one tenth out of the water, and 
is exposed to a draught of air on a warm summer’s day, the 
tumbler itself being also surrounded by this warm air. When 
snow melts in the hand a painful sensation of cold is produced, 


21. What is the design of the principle of latent heat ? 



GENERAL PRINCIPLES AND LAWS. 


21 


and when on the feet, it often causes violent colds and other 
diseases. 

The amount of latent heat varies greatly with different sub¬ 
stances, as appears from the following table : 


Water, 142°. 

Sulphur, 17°. 

Lead, 9°. 


Zinc, 49°. 

Tin, 26°. 

Bismuth, 22°. 


22. The design of this principle of latent heat is obvious. 
It is a most effectual rampart against disastrous floods, which 
would arise from the too sudden melting of snow in spring. It 
retards the advance of winter, and delays the approach of 
summer, rendering the progress of one season to another more 
gradual. It tends to give greater uniformity to climate, and to 
prevent the alternation of warm days and sudden frosts, by 
which fruits are cut off and vegetation injured. 

23. When liquefaction can he by any means hastened, the 
intensity of the cold is increased, the whole amount being pro¬ 
duced in a shorter time. In freezing mixtures, (M* this, is 
accomplished by a principle of very frequent occurrence in 
chemistry, and of great importance, called catalysis, 'presence- 
action, or contact-action. In this case, a body, by its mere 
presence or contact, induces changes in another, in which it 
takes no part. Thus, when salt is mixed with snow, the pres¬ 
ence of the salt hastens the liquefaction of the snow, with 
which, however, it does not unite until it is converted to water. 
So, if starch is boiled in a little weak sulphuric acid, it is con¬ 
verted into sugar; and if, at the termination of the process, the 
acid be examined, it will be found to remain unaltered, both 
in properties and quantity ; so that the smallest proportion of 
the acid is sufficient to convert into sugar an indefinitely large 
quantity of starch. 

24. On the other hand, the congelation and the diminution 
of volume of any body, will cause a portion of its latent heat 
to become sensible. Water becomes solid in the process of 

* These numbers refer to experiments and illustrations at the end of the 
hook. * 


21. Why is liquefaction a cooling'process ? How is this illustrated ? What 
is said of the latent heat of different substances ? 

22. What is the design of the principle of latent heat ? 

23. What produces the intense cold of freezing mixtures ? 

24. What is the effect of the congelation of a body upon its latent heat ? 
Does the diminution of volume produce the same effect ? Why does iron give 
out heat when hammered? Why is heat given out in the process of slaking 
lime? 




22 


ELEMENTS OF CHEMISTRY. 


slaking lime, and the heat given out is so great as to set fire 
to light and combustible bodies. Ships freighted with lime are 
in this way sometimes set on fire. Sulphuric acid and water, 
when mingled, are condensed into a smaller volume, and great 
heat is produced. 

Congelation produces heat by giving out the heat which is 
essential to the liquid form, when that liquid is converted into 
a solid. The freezing of water produces heat, because the heat 
which was latent in the water, becomes ^sensible when the 
water returns to the frozen state. 

Congelation is a 'purifying process. The waters of the sea, 
by freezing, are deprived of all their salt, and in very cold 
countries, as in the region around the White Sea, in the north 
of Europe, this process is used to concentrate the salt waters 
of the sea, and thus to shorten the subsequent process of evap¬ 
oration. 


VAPORIZATION AND EVAPORATION. 

25. The conversion of fluids into vapors, when performed 
artificially, is called vaporization; when it occurs naturally, 
evaporation. When vaporization is carried on rapidly, a vio¬ 
lent agitation of the fluid takes place, to which the term ebul¬ 
lition is applied. Ebullition is caused by the formation of 
vapor, on the side next to the heat which rises through the 
fluid, and is succeeded by another portion formed in the same 
way, and thus the process is continued until the heat is re¬ 
moved, or the liquid is entirely converted into vapor. Water, 
when converted into vapor, expands 1696 times, alcohol 660 
times, and ether 443 times. 

26. The boiling point is that temperature at which a liquid 
undergoes ebullition Thus mercury boils at 662° ; oil of tur¬ 
pentine at 316° ; water at 212° ; alcohol at 173° ; and ether 
at 96°. The circumstances which attend the ebullition of flu¬ 
ids always affect its boiling point. Among these are the fol¬ 
lowing : 

(1.) The boiling point varies with the pressure in all liquids ; 
in each according to a special law. In the same liquid, it 
rises or falls as the pressure is increased or diminished. 

(2.) The boiling point changes with the nature of the vessel 
in which the liquid is boiled. Pure water boils in a metallic 


25. How is vaporization defined? Evaporation? What is meant by the 
term ebullition? What is the cause of ebullition? How much does water 
expand when converted into vapor ? Alcohol ? Ether ? 

26. What is meant by the boiling point of a liquid? What examples are 
given / What ettect has pressure upon the boiling point of liquids ? The na- 



GENERAL PRINCIPLES AND LAWS. 


23 


vessel at 212°, under the ordinary pressure of the atmosphere, 
while its boiling 1 point in a glass vessel under the same pres¬ 
sure is 214°. r 

(3.) The boiling point is altered by the presence of foreign 
substances in the liquid. Ether, heated in a glass vessel, 
has its boiling point lowered nearly 50° by the introduction 
ol a. few small cedar chips, and alcohol between 30° and 
40°. The boiling point of water, heated in a glass vessel, 
was brought down 4° or 5° by the same means. Liquids 
heated in glass vessels may he made to boil several' de¬ 
grees lower, by adding coils of wire upon which the liquid 
does not act, as coils of fine platinum wire to sulphuric acid. 
If two similar glass vessels be taken, the one coated in the 
inside with a film of shellac, and the other cleansed by hot 
sulphuric acid, water heated over a lamp in the first, will boil 
at 211°, while in the second, owing to an attraction between 
the clean surface of the glass and the liquid, it will often rise 
to 221°, or even higher. A momentary burst of vapor then 
ensues, and the thermometer sinks a few degrees, after which 
it rises again. In this state the introduction of a few metallic 
filings, or angular fragments of any kind, occasions a lively dis¬ 
engagement of vapor, while the temperature sinks to 212°, and 
remains stationary. 

(4.) The ebullition of liquids is affected in a very peculiar 
manner, when they are projected on a surface heated consid¬ 
erably above their usual boiling point. Water, when poured 
on a surface heated to 298°, assumes a spheroidal form, rolls 
about rapidly, and evaporates very slowly. At 392°, a grain 
and a half requires 3.30 minutes to evaporate; at a dull red 
heat, the same quantity will last 1.13 minutes, and at a bright 
red heat, 0.50, the rate of evaporation increasing with the 
temperature. The water does not touch or wet the hot sur¬ 
face, but is kept at a sensible distance frdfcri it by the elastic 
force of an atmosphere of its own vapor. This vapor not only 
in its formation abstracts heat from the liquid, but by its non¬ 
conducting properties retards the passage of the heat from the 
ignited surface. Notwithstanding, therefore, the proximity of 
red-hot metal, the temperature of the liquid in this state is 
found to be always lower than its boiling point. The temper- 
ature of water in the spheroidal state is 206°, that of alcohol 
168 3 , and that of ether 91°. 

27. By increasing the pressure on the liquid, the boiling 
point may be raised indefinitely ; and this increased tempera¬ 


ture of the vessel in which the liquid is boiled ? The presence of foreign sub¬ 
stances ? What is meant by the spheroidal state of bodies ? 



24 


ELEMENTS OF CHEMISTRY. 


ture has been found to give additional and very important 
properties to water and to steam. A strong metallic vessel, 
called Papin’s Digester, in which water may be heated under 
a powerful pressure, has been sometimes employed in dissolv¬ 
ing hard animal substances, which cannot be dissolved by boil¬ 
ing in the ordinary way. Soups are sometimes prepared in 
this manner, and in the laboratory, substances are dissolved 
otherwise not easy of solution. When steam at a high pres¬ 
sure and temperature is turned upon peat, it deprives it of its 
water, turns it to charcoal, and causes the distillation of a great 
variety of substances. After this exposure, peat takes fire on 
contact with air, if it is cooled down away from the atmosphere 
of steam. If different kinds of wood are exposed to steam 
heated to 482°, they diminish greatly in weight. Elm and 
oak were, by this method, made to decrease in weight one half, 
ash and walnut two fifths, and pine one third. A change of 
color was also observed as the heat was rising from 382° to 
482°. A kind of tar was formed which was found to have a 
preserving effect on the wood. The strength of the latter was 
increased. The oak gained in strength five ninths, walnut one 
half, pine two fifths, and elm over one fifth. The maximum 
heat for producing strength was, for elm from 302° t^ 347°, 
for oak, walnut and pine from 257° to 302°. The fibres of 
the wood were drawn closer together, and maple and pine 
treated with steam at a temperature of 482°, were rendered 
far more valuable for musical instruments, than by any process 
before known The expansive force of water is greatly aug¬ 
mented when thus heated in a confined state. At a tempera¬ 
ture of 400°, this force equals 16 times the pressure of the 
atmosphere, or about 240 pounds to the square inch. 

28. Under a given pressure , the temperature of liquids , 
while boiling , remains the same. This is true whether they 
are boiled with a Mgh, or a moderate heat. The effect of an 
intense fire, is only to increase the rapidity of the ebullition 
This is owing to the fact, that water in being converted into 
steam , renders latent a great amount of sensible heat. When 
water at 32° is mixed with an equal weight of water , at 212°, 
the whole is found to possess a mean between the two temper¬ 
atures, or 122° ; but when equal weights of water and steam 


27. What is the effect of increasing the pressure on fluids ? For what pur¬ 
pose is Papin’s Digester sometimes employed 1 What effect has steam at a 
high temperature and pressure upon peat ?—upon wood ? What is said of the 
expansive force of water when thus heated under pressure ? 

28. What effect is produced by an intense fire on the ebullition of fluids ? 
What is the latent heat of steam ? How is this proved 1 




GENERAL PRINCIPLES AND LAWS. 


25 


are mixed, or an equal weight of steam is condensed in water 
at 32°, it raises 5 6 parts of the latter up to the boiling point, 
or through a range of 180°. Multiply, therefore, these 180° 
by the 5*6 parts of water, (180°x5 , 6=:1008 0 ,) and it equals 
1008°. Therefore, the steam has added to the temperature 
of the water in which it was condensed 1008°, or has lost this 
amount of heat at the same time with its aeriform state, or 
its change into water. Therefore, 1008° may be considered 
as the latent heat of steam. 

29. Another method gives nearly the same results. Five 
gallons of water are heated in Papin’s Digester to 400°. A 
vent is suddenly given to the steam, and one gallon allowed 
to escape in the form of steam. This sudden conversion of 
one gallon into steam, reduces the temperature of the remain¬ 
ing four gallons to 212°. Five gallons, therefore, (including 
the steam which escaped at 212°,) have been reduced to 212°, 
and have, consequently, lost (400 — 212=) 188°. Multiply 
this number by 5, and 940° is the amount of sensible heat lost, 
or that which has become latent in the steam. The former 
method gave 1008°, which is probably nearer the truth, as the 
latter method is not as susceptible of great accuracy. 

30. The vast amount of heat which steam absorbs, is given 
out again when it is condensed. Hence the value of steam 
as a source of heat, for which it is used, in warming apart¬ 
ments, in drying gunpowder, and other purposes, where a mild 
uniform temperature is required. In the laboratory, steam 
baths, of various forms are used for the purpose of drying fil¬ 
ters and other objects where excessive heat would be hurtful. 

Fig. 12, represents a very simple and conve¬ 
nient form of the steam-bath. Tne lower part, Fig. 12. 

< 2 , is a common steam-boiler. The upper part, 
b, is made double ; between the inner and outer 
portions, a space is left for the steam to pass, 
which issues near the top, at the small hole, c. 

The space within this upper part, is therefore 
kept by the steam continually at the boiling 
point, or 212°, and filters or other objects placed 
within this, are soon dried at this temperature. 

The vapors of other liquids have less latent heat than water, 
as is shown in the following table : 



29. Give the second proof. 

30. To what is the value of steam, as a source of heat, owing? Explain 
Fig. 12. How do the latent heats of other liquids compare with that of 
water ? 


2 





26 


GENERAL PRINCIPLES AND LAWS. 


Vapor of Water, . . 

“ Alcohol, 

“ Vinegar, 

“ Ether, . . 

“ Turpentine, 


. 966-924. 

. 374-958. 

. 183-438. 

. '163-998. 
. 123-714. 


31. Steam. All the properties of steam have been very care¬ 
fully studied on account of its vast mechanical power, and its 
exceedingly numerous and valuable applications in the arts. 
As the description of the steam-engine , belongs more properly 
to mechanical philosophy, than to chemistry, it will be omitted 
in this work. (See Olmsted’s Natural Philosophy.) The 
leading properties of steam may be included under the follow¬ 
ing heads: 

1. Steam is only about half as heavy as air, and the spe¬ 
cific gravity of ivatery vapor, or vapor produced at a tem¬ 
perature below the boiling point, is much less, varying with 
the temperature at which it is formed. The specific gravity 
of watery vapor at different temperatures, is shown in the fol¬ 
lowing table : 


Temp. 

Sp. gr. 

32° 

5-690. 

50° 

10-293. 

60° 

14-108. 

100° 

46-500. 

150° 

170-293. 

212° 

625-000. 


At 212°, therefore, or the boiling point of water, its vapor, or 
steam, is a little more than half as heavy as air. 

(2.) The elastic force of steam, or watery vapor, at the 
common pressure of the atmosphere, is 15 pounds to the square 
inch. This is evident in the case of steam, for when issuing 
from a boiler, it will force out the air from the boiler, or from 
any cylinder with which it may be connected, thus overcom¬ 
ing the pressure of the atmosphere, which is 15 pounds to the 
square inch. This pressure is owing to the mutual repulsion 
of the particles, (p. 11,) which is caused by the elevation of 
their temperature. 

(3.) When heated in a confined situation over ivater, the 
elasticity of steam is very rapidly increased, and is thus ren¬ 
dered superior to any other mechanical force within our con¬ 
trol. 


31. What is the first of the leading properties of steam?—the second? 
How is this proved ? Give the third leading property of steam;—the fourth;— 
the fifth. 





GENERAL PRINCIPLES AND LAWS. 


27 


(4.) When steam is heated or cooled, not in contact with 
water, its expansion or contraction is the same as that of the 
'permanent gases (18) under the same circumstances. 

(5.) The latent heat of steam diminishes as the temperature 
of the steam rises, so that equal weights of steam thrown into 
cold water, exhibit the same heating power, although the actual 
temperature of the one portion may be 212°, and that of the 
other 350° or 400°. This is also true at temperatures below 
the boiling point. It is, therefore, necessary to employ the 
same absolute amount of heat to evaporate a given quantity 
of water, whether the evaporation takes place slowly at the 
temperature of the air, or is performed by boiling under a pres¬ 
sure of 20 atmospheres, and at a temperature, consequently, 
of 418°. From this it follows that, although water boils at a 
lower temperature under diminished pressure, or in a vacuum, 
no direct saving of fuel is in this way effected. This process 
is, therefore, employed in boiling sugar, to effect a saving of 
this substance, by boiling at a low temperature, rather than a 
saving of fuel which would be required to produce a higher 
temperature under the pressure of the atmosphere. 

32. Evaporation. Natural evaporation is that process by 
which vapor rises spontaneously from fluids. Operating upon 
the entire waters of the globe, it is a most powerful agent in 
the economy of nature. The quantity that rises from an acre 
of land varies according to circumstances. Over land covered 
with dry grass, in the heat of summer, it has been estimated 
at 1600 gallons, and on moist grounds, it has amounted in 
some instances, to 5,000 gallons. A circular area of snow , fivo 
inches in diameter, lost 150 grs. between sunset and sunrise, 
and 50 grs. more before night. In this experiment the snow 
was exposed to a smart breeze upon a house-top ; an acre of 
snow exposed to a similar breeze, would lose in the same time, 
66,000,000 grains, or 11,111 pounds of moisture. During the 
night, about 1,000 gallons of water would be raised from an 
acre of snow. The ocean loses many millions of gallons 
hourly by evaporation. 

33. The circumstances most favorable to evaporation are the 
following : 

(1.) Extent of surface. This is true also in vaporization, 
or in boiling down liquids ; the vaporization of water in a 
flask, for instance, will proceed much faster when the water is 
half boiled down, than when the flask is nearly full, because a 


32. How is evaporation defined ? What is said of its extent 1 

33. What are some of the circumstances which are most favorable to evapo¬ 
ration ? What examples are mentioned under the first head? Why does a 



28 


ELEMENTS OF CHEMISTRY. 


greater extent of surface is exposed, and the same water in a 
wide evaporating dish, will boil away much quicker than in 
a deep one. 

(2.) A free current of air. When the air rests on the sur¬ 
face of the fluid, that portion next to the surface of the fluid, 
soon becomes saturated, and, unless a fresh portion be supplied, 
the evaporation will he greatly retarded. But if, as fast as 
the air above becomes saturated, another portion supplies its 
place, the evaporation will be rapid. In an open vessel, the 
evaporation will be much greater than in a flask, which ex¬ 
poses an equal surface of the liquid, and in the open air than 
under the cover of a building. 

(3.) Agitation. By means of this, a greater surface is ex¬ 
posed, and vapor that has been imprisoned within the body of 
the fluid, has an opportunity of escaping. 

(4.) A dry state of the air , and an elevated temperature. 
A certain amount of moisture is due to every temperature, and 
as the temperature is raised, this amount is very greatly in¬ 
creased. When the air is dry, the force of evaporation to sup¬ 
ply the deficiency of watery vapor, is very great, and, like the 
force with which air rushes into a vacuum, this diminishes 
with the supply, until, when the quantity due to the temper¬ 
ature is nearly supplied, the evaporation is very slow. The 
same process is observed, when gases are absorbed by water, 
or watery solutions. The force of absorption diminishes, till 
near the point of saturation it becomes very slow. 

How important is the broad expanse of water upon which 
we look with so much pleasure! Even the wide surface of 
the ocean, added to that of all the rivers and lakes, is not too 
great to afford sufficient water for vegetation on land, and for 
copious, unfailing"springs to support animal life. The surface 
of the ocean is broader towards the equator than in the tem¬ 
perate zones ; and hence, as well as from the greater heat of 
this region, a greater amount of evaporation is produced, and 
consequently much more rain falls on the central portions of 
the earth. 

3<±. The effects of evaporation are of the most important 
character. 

(1.) Evaporation renders salt water fresh. Pure water 


free current of air promote evaporation ? Why is evaporation promoted by 
agitation 1 —-by a dry state of the air, and an elevated temperature ? What is 
said of the importance of the ocean, and lakes, and other broad surfaces of 
water ? 

34. What are some of the effects of evaporation ? What is the first impor¬ 
tant effect ?—the second ? How does evaporation regulate the heat of the body ? 




GENERAL PRINCIPLES AND LAWS. 


29 


rises from the sea in. clouds, which are carried over the land, 
where they deposit their moisture. Were not this the case, it 
is evident that the vapors which come from the ocean would 
soon impart their saltness to all the waters of the globe, and 
a stream of fresh water would be unknown, much less that 
great abundance of pure water which we now have, and which 
is necessary to our existence. 

(2.) Evaporation produces cold. This is the great agent 
which nature employs to check the excesses of solar heat, since 
this heat itself is made to generate vapor with a rapidity pro¬ 
portioned to its intensity ; this vapor converts sensible- into 
latent heat, during its formation, and thus maintains a per¬ 
petual check upon the violence of the sun’s rays. Among the 
contrivances of art, none is more admirable than the governor 
of the steam-engine, by means of which the flow of steam from 
the boiler is regulated, exactly according to its amount and 
pressure ; but in this controlling force of nature, a power of 
escape is afforded to the heat of the earth, which increases 
with much greater rapidity than the heat itself, that the 
moderate heat which animal life can endure may not be ex¬ 
ceeded. 

Evaporation also tends to regulate the heat of the human 
system. From every part of the body, moisture is continually 
given off through the pores, and a vast quantity is exhaled from 
the lungs. Perspiration, which is greater in warm than in 
cold weather, keeps the body nearly at a uniform temperature 
whatever be the state of the atmosphere. Indeed the human 
system has been exposed to a heat considerably above that of 
boiling water, without injury, so effectually did evaporation 
from perspiration protect it. The circulation of the blood and 
perspiration are in continual equilibrium in the human system ; 
what affects the one affects also, in an equal degree, the 
other. Violent action or excitement, quickens the circulation 
of the blood, and also greatly increases the amount of perspira¬ 
tion. 

DISTRIBUTION OF HEAT. 

35. For the safety of the world there is impressed on heat a 
most powerful tendency towards an equilibrium. Whether 
coming from the sun, or produced by artificial fires, the heat 
of any particular place is no sooner increased above that of the 
surrounding medium, than the excess endeavors to make its 


35. By what four methods is heat distributed 1 




30 


ELEMENTS OF CHEMISTRY. 


escape in every way, and can be retained only by the greatest 
pains and skill, even for a few moments, All objects around 
us, are naturally of the same temperature, and the heat of the 
equator is soon dissipated towards the poles. By four methods 
heat is distributed : by radiation , by reflection , by conduction , 
and by convection. 

36. (1.) Radiation is the emission of heat in right Lines 
from the surfaces of bodies. From reflection, it differs in the 
source or origin of the heat which is emitted, which in radia¬ 
tion is from within the body, but in reflection, is from without 
the body. A body radiates its own heat, and loses heat by 
radiation, but reflects the heat of other bodies from its surface, 
and therefore, sustains no diminution of temperature by reflec¬ 
tion. 

37. The sun and all ignited and burning bodies, afford the 
most striking examples of the radiation of heat, although all 
hot bodies, as hot stoves, steam-boilers, &c., likewise radiate 
heat. 

38. The power of radiation depends greatly on the nature 
of the surface. It proceeds much more rapidly from a rough 
surface than a smooth one, and from a black surface, than from 
one of any other color, and least of all, from a white surface. 
Not only the colors applied, but the thickness of the coloring 
matter affects the radiation of heat from surfaces. This has 
been shown by M. Melloni, who covered the surfaces of a 
metallic vessel with successive layers of varnish, measuring 
each time the heat radiated from the surface. This he found 
to increase up to the seventeenth layer of varnish, when it be¬ 
came stationary. Gold leaf with a much thinner coating pro¬ 
duced an equal amount of radiation. 

39. Bodies that absorb most heat , radiate most , although 
the amount of absorption and radiation are not always 'pro¬ 
portional to each other. Snow melts more rapidly when soot 
or dark earth is scattered upon it, because it then absorbs heat 
more rapidly from the sun. Grapes and other fruits ripen 
quicker against dark walls, than those having a light color, 
because these walls absorb heat, which they comjnunicate to 
the grapes and the air by which the grapes are surrounded. 


36. How is radiation defined ? How does radiation differ from reflection ? 
Why does a body lose heat by radiation ? Why does it lose no heat by reflec¬ 
tion ? 

37- Mention some examples of bodies that radiate heat ? 

38. Upon what does the power of radiation greatly depend ? Ans.—Upon the 
nature and thickness of the coloring matter. 

39. How are absorption and radiation related to each other? Mention some 
examples showing the effect of color on absorption. 



GENERAL PRINCIPLES AND LAWS. 


31 


If three tumblers be enveloped, one with silver paper, an¬ 
other with white, and another with dull black paper, and all 
be placed in the sun, a thermometer will -indicate that the 
tumbler with black paper, absorbs most heat in a given time, 
and that with the silver paper, the least. 

40. The following rules for the practical management of 
heat, are derived from the foregoing principles : 

For confining heat , no surface is so effectual as a bright 
metallic one. This also should be as smooth as possible, for 
the minute points and edges of a rough surface dissipate the 
heat rapidly. Among the various colors, white is the best for 
confining heat; hence while houses are warmer in winter than 
those of a darker color, as the loss of internal heat by radia¬ 
tion, is not so great from these as from other houses ; they are 
also cooler in summer, as they absorb less heat, or reflect more. 
Pipes intended for conveying heat to distant apartments should 
be bright and smooth, but those intended for warming a room, 
should be rough like sheet-iron. 

We may regulate our apparel on the same principles. If 
we are to expose ourselves to the sun in hot weather, white 
clothes should be selected, as white absorbs less heat, or re¬ 
flects more than any other color. If we are to continue in 
the shade, black garments are more suitable, as black radiates 
heat more than any other color. 

41. The power of absorbing heat, possessed by cloths of 
different colors, was tested by Dr. Franklin in the following 
manner : He took pieces of cloth of four different colors,— 
black, blue, brown and white, and laid them on the snow, in 
the direct rays of the sun. After a few hours, it was found 
that the black had sunk to a considerable depth, the blue not 
so far, the brown still less, and the white hardly at all. From 
this experiment, it was inferred that black is the warmest 
color in the sun, or absorbs the most heat ; blue, the next; 
brown absorbs less heat than blue ; and white is the coolest 
of all the colors. In the cold days of winter, therefore, when 
the heat of the body escapes most rapidly, a white overcoat is 
to be preferred, to check the loss of heat by radiation. This 
color is chosen by Nature, when she wraps the Northern hemi- 


40. What is the first rule for the management of heat derived from these 
principles ? Why are white houses warmer than those of a darker color ? Of 
what should pipes, intended for conveying heat, be made ?—for diffusing heat ? 
What clothes are most suitable for wearing in the sun during hot weather ?— 
in the shade ? 

41. Mention, the experiments tried by Dr. Franklin. What is the warmest 
garment for winter? What is said of the snow and the animals of the Frigid 
Zone? 



32 


ELEMENTS OF CHEMISTRY. 


sphere with a mantle of snow, or clothes the animals of the 
frigid zone for the intense cold of their winters. Some of these 
animals even change their color at the approach of winter, as 
some varieties of the hare. 

42. Reflection is, like radiation, the emission of heat from 
bodies in right lines, hut it differs from the latter, in the source 
of the heat, which is from without, or external to the body 
causing reflection. That bodies which absorb the most heat, 
must reflect the least, is evident, for all that is absorbed is, of 
course, taken from that which is reflected. Absorption and 
reflection are therefore opposite. Reflection and radiation are 
also opposite, for, as stated above, bodies that absorb most also 
radiate most. If, therefore, a body radiates more than another 
body, we know that it also absorbs more, but reflects less. All 
the rules given above, for radiation and absorption will, if re¬ 
versed, apply to reflection. 

43. Conduction is the propagation of heat through the 
substance of bodies. This passage of heat through some sub¬ 
stances, is much more rapid than through others. Accordingly, 
bodies are divided into conductors and non-conductors of heat 
The former are those that conduct heat readily ; the latter, 
those that conduct heat with difficulty, or not at all. Among 
the conductors, are the metals and stones. Perhaps there is 
no absolute non-conductor of heat, unless the air, and some 
of the gases, be considered as such ; but in this class are in¬ 
cluded such bodies as bricks, wool, feathers, most of the liquids, 
and the gases. 

If two similar rods, one of iron and the other of glass, be 
held in the flame of a spirit-lamp, the iron will soon be too hot 
to be touched, while the glass can be held within an inch or 
two of the red-hot portion. 

44. The different conducting powers of several substances, 
may be illustrated by little cones (Fig. 13,) of copper, iron, 

wood, &c., placed on a double metallic plate, 
which is heated by a lamp from beneath. The 
heat is uniformly distributed over the upper plate, 
by the heated air which rises from the lower, 
and is therefore communicated to the bottom of 
all the cones alike. The heat, however, rises to 


Fig. 13. 



42. How is reflection defined ? How are absorption and reflection related ? 
Why are reflection and radiation opposite ? 

43. How is conduction defined? What is meant hy conductors and non¬ 
conductors of heat ? Mention some examples of conductors ;—some examples 
of non-conductors. What experiment illustrates the conducting power of iron 
and the non-conducting power of glass ? 

44. Explain Fig. 13.—Fig. 14. 




GENERAL PRINCIPLES AND LAWS. 


33 


the summits of these cones at very different rates. If a ball 
of wax be placed on each of these summits, on the copper cone 
the wax will be melted first, and the ball will drop off; on 
the iron, the next ; while on the wood the wax will remain 
unmelted. If bits of phosphorus be placed on the cones, they 
will be fired in the same order of copper, iron, &c. 

If several marbles be 

stuck with wax on a cop- Fig. 14. 

per wire (Fig. 14,) and V 6 6 0 6 6 A 1 

one end of the wire be A 

held in the lamp, as the ^ 

heat travels through the wire the marbles will drop off one 
after another. 

45. In the following table are given the relative conducting 
powers of several substances, gold being 1000 : 


Gold, 

1000. 

Zinc, 

363. 

Silver, 

973. 

Tin, 

304. 

Copper, 

898. 

Lead, 

180. 

Platinum, 

381. 

Marble, 

23.6. 

Iron, 

374. 

Porcelain, 

12.2. 


From this table, it appears that the conducting power of 
gold is nearly three times that of iron ; that of copper is more 
than twice that of iron, while lead has not half the conducting 
power of iron. Bodies not metallic, as marble and porcelain, 
are much poorer conductors of heat than the metals; and 
fire-clay and wood, are still worse, conductors. Heavy, solid 
wood, is a much better conductor than that which is light and 
porous. In the list of non-conductors may be reckoned dry 
bricks, wool, feathers, hair, fur, &c. It is owing to this prop¬ 
erty, that the latter are used for clothing, and bricks in the 
construction of houses. The value of this class of bodies as 
non-conductors, is destroyed, or greatly impaired, by the pres¬ 
ence of moisture. Thus straw is a good conductor when wet, 
but a bad conductor when dry. Wet garments are unhealthy, 
as they carry off the heat of the body, and thus produce vio¬ 
lent colds and fevers. 

46. Snow is admirably adapted as a protection to the earth, 
(1.) by its color, which prevents loss of heat by radiation ; (2.) 
by its non-conducting properties, as it is one of the best non- 


45. How do the conducting powers of gold, copper, and lead, compare with 
that of iron ? What is said of the conducting power of non-metallic bodies 1 
Mention some of the non-conductors. What is the effect of moisture on these 
bodies 1 Why are wet garments unhealthy ? 

46 In what way does snow serve as a protection to the earth / 

2* 






34 


ELEMENTS OF CHEMISTRY. 


conductors; (3.) by its light, downy texture, which causes it 
to fall gently to the earth, imprisoning much air between its 
crystals, and leaving the earth open and porous beneath ; (4.) 
by its temperature, which is very moderate, compared with 
that which prevails during the coldest days of winters ; hence 
the warmth of the snow-huts of the Esquimaux, and the pro¬ 
tection of their springs of water, during the intense cold of their 
winters. The surface of the earth covered with snow, is pro¬ 
tected at the temperature of the freezing point, and imme¬ 
diately below the surface the temperature is much higher. 
The roots of plants are preserved, and the fermentative pro¬ 
cesses of vegetable decay are carried on ; the soil thus- imbib¬ 
ing fertility in the midst of winter, and being prepared to re¬ 
ceive the rays of the sun in spring. (5.) The latent heat of 
snow has already been noticed. This adds greatly to its value, 
preventing inundations, which would be produced by its sudden 
melting in spring, and retarding the too sudden approach of 
winter. The snow of winter is, therefore, not only its orna¬ 
ment but its protection, and by this in winter, Nature pre¬ 
pares the beauty of summer and the bounty of harvest. 

47. Convection is that method by which 
heat is conducted in fluids ; it may be defined, 
the conduction of heat in fluids , by a motion 
among their particles The common mode 
in which liquids are heated, is represented in 
Fig. 15. A lamp is placed beneath a glass 
vessel, made of thin (9.) glass. A current 
of hot water rises (for the particles of water 
being expanded by heat, become lighter) in 
the centre to the top, where it becomes cooled, 
and then descends on the sides. This pro¬ 
cess is kept up until the whole body of the 
water is heated. When the temperature of 
the water is thus raised to 212°, boiling suc¬ 
ceeds, in which vapor, and the water which 
it carries up mechanically, rises in the centre, and the remain¬ 
der of the water descends on the sides. 

48. When the water on the surface of the ocean is cooled 
down lower than that beneath the surface, it descends, and 
warmer portions ascend, which are cooled in the same manner. 
Currents also from the polar regions flow towards the equator, 
and from the equator other currents flow to the northern and 
southern latitudes. In this way, the heat of the ocean is dis- 


Fig. 15. 



47. How is convection defined 7 Explain Fig. 15.- 

48. How is heat distributed in the waters of the ocean ?—In the atmosphere 7 




GENERAL PRINCIPLES AND LAWS. 


35 



tributed throughout its mass, above and below, in warm and 
in cold latitudes. In the air, and in all vapors and gases, the 
same thing happens. The rays of the sun pass through trans¬ 
parent media, without affecting their temperature. Only those 
portions of the atmosphere, therefore, which come in contact 
with the earth, are heated. These rise, and their place is 
supplied by colder portions, and thus the heat of the earth is 
distributed throughout the atmosphere. 

49. But without this convection, or carrying pro¬ 
cess , the conducting power of liquids and gases is 
very small. If a test tube, nearly filled with water, 
be held over a spirit lamp inclined in such a man¬ 
ner as to direct the flame against the upper layers 
of the water, the water will boil at the top, but re¬ 
main cool below. In Fig. 16, a jar of water is per¬ 
forated at a and b, for two thermometers, and sur¬ 
rounded at c with a metallic trough. Into this trough boiling 
water is poured. After some time it will be found that the 
upper thermometer has risen, while the lower has remained 
perfectly stationary. The upper part of the fluid is heated by 
convection, while the lower part can be heated only by con¬ 
duction. 

The same principle is illustrated in a differ¬ 
ent manner, in Fig. 17. a b c is a tall jar, or 
wide tube ; d a ring of iron provided with a 
handle. Into a be, a little water, colored blue, 
is poured as high as a; water not colored is 
then added as high as b, and the portion from 
b to c, is filled with a yellow solution. If the 
ring d, is heated red hot, and applied to the 
tube or jar between b and c, the yellow portion, 
b c, may be made to boil without intermingling 
with the colorless portion, a b. But if the red- 
hot ring be lowered down, so as to surround the 
blue portion, it will, as it becomes warm, ascend 
first through the colorless stratum, and finally 
through the yellow solution at the top. If a piece of ice be 
suspended in the empty jar, and the red-hot ring applied to 
the portion of the jar above, it will continue to melt very slowly, 
as before the ring was applied ; but if the ring be carried down 
the jar below the ice, it will melt much more rapidly. 


Fig. 17. 



4Q what is the conducting power of liquids and gases when heat is not dis¬ 
tributed ! How may this be shown by a test tube 

nearly 1ailed^with wSe/and held over the flame of a lamp ? Explain Fig. 16. 
-Fig- 17. 





















36 


ELEMENTS OF CHEMISTRY. 


50. Air, by its non-conducting properties, enhances those of 
all other substances, and is, to a great extent, the cause of the 
non-conducting power of most substances. It not only sur¬ 
rounds all bodies on the earth, but fills the pores of almost all 
bodies. Were air, therefore, a good conductor, snow, wood, 
feathers, water, and all those light bodies which are remarka¬ 
ble for their non-conducting power, would become conductors, 
and other bodies would avail little in retarding the escape of 
heat, being surrounded on all sides by a good medium of 
transmission. Our dwellings could not be warmed, for air en¬ 
tering the smallest crevices, and pervading the materials of 
which they are constructed, would carry off the heat as fast 
as it was generated. The smallest dew-drops, and the vast 
atmosphere, are formed with the same wisdom and benevo¬ 
lence ! 

51. Applications of the non conducting properties of air, 
are seen in the construction of furnaces for heating buildings, 
where confined air is often used to prevent the heat from es¬ 
caping from the sides of the furnace. The common refrigera¬ 
tor , for keeping ice a long time without melting, is constructed 
with a space of confined air between the inside and outside. 
Ice houses are made with double walls, between which is 
placed charcoal, fine saw dust, or some other light substance ; 
or this space is occupied merely by confined air. In northern 
countries, the houses are provided with double windows and 
doors, and thus a portion of air is confined, which effectually 
excludes the cold. 

QUANTITY OF HEAT IN BODIES. 

• 52. Latent heat is observed, when bodies are changing their 

form from the solid to the liquid, or from the liquid to the 
aeriform state. But another equally remarkable phenomenon 
of heat is observed, in the amount necessary to raise different 
bodies to a given temperature, even without a change of form. 
This is called specific heat. It may be illustrated in the follow¬ 
ing manner : 

Put as many marbles into a glass as it will contain. When 
the vessel is full of marbles, add as much sand as will pene¬ 
trate and lodge between the marbles. Fill also another glass 
with pebbles, which will arrange themselves in a more cojn- 


50. What is said of the non-conducting properties of air ? 

51. What applications are made of the non-conducting properties of air ? 

52. What is specific heat ? How does it differ from latent heat ? How is it 
illustrated ? 





GENERAL PRINCIPLES AND LAWS. 37 

pact form than the marbles. Pour sand into the second glass 
and it Mull he found to contain less than the first. As a greater 
amount of sand enters the interstices of the marbles than 
those of the pebbles, so different quantities of heat may be 
supposed to enter and pervade the interstices of the constituent 
atoms of bodies. 

53. Take a pound of oil at 40° and a pound of water at 
100°, and agitate them together. The temperature of the 
mixture will not be the mean between the two, or 70°, but the 
thermometer will stand at 80°. Reverse the experiment, and 
with a pound of oil at 100° mix a pound of water at 40° ; the 
temperature of the mixture in this case, will fall below the 
mean, and will be at 60°. These results may be compared 
numerically, in the following way : 

-pi 1 1 lb. of water, at 100°, ) give a mixture at 80°. 

1 1 lb. of oil, at 40° O, ] Mean = 70 ( 2 ). 

•p, ~ 1 lb. of water, at 40°, ) give a mixture at 60°. 

P * 1 lb. of oil, at 100° ( 3 ), $ Mean=70 ( 4 ). 

From both these experiments it appears, that water has more 
heat at the same temperature than oil, for in the first case it 
raised the oil (*) above the mean ( 2 ,) to 80°, and in the second 
case, it sank the temperature of the oil ( 3 ) below the mean ( 4 ) 
to 60°. In the first instance, it heated the oil more than it 
lost heat itself; in the second, it took from the oil more than 
it gained itself, as indicated by thermometer. The first result 
was the loss of 20° by the water, and a gain of 40° by the 
oil; the second, a loss of 40° by the oil^and a gain of 20° by 
the water. We may therefore conclude, that 20° of heat in 
water, is equal to 40° in oil, or that the specific heat of water 
is twice that of oil; it takes twice as much heat to raise water 
to a given temperature , as it does oil to the same temperature. 

54. In forming a table of specific heats, water is selected as 
a standard. With water, other liquids may be compared, by 
the method of mixtures given above. In the case of a solid, 
the same method may be adopted. If a bar of copper, of a 
pound weight, be heated to the temperature of 320°, and 
plunged into water at 70°, when both have acquired the same 


53. In what way may the specific heats of water and oil be compared 1 How 
much more heat does it take to raise water to a given temperature than oil to 
the same temperature ? 

54. Jn forming a table of specific heats, what is taken as the standard ? By 
what method may the specific heats of liquid be compared with that of 
water ?—solids ? Iq what manner may the specific heat of a bar of copper be 
determined ? 



38 


ELEMENTS OF CHEMISTRY. 


temperature, this will be found to be 92°. This stated in num¬ 
bers is as follows : 


1 lb. of copper, at 320°, 
1 lb. of water, at 70°, 


320°—92° = 228° ( x ). 
Common temperature, 92°. 
92°—70° = 22° ( 2 ). 


The copper has therefore lost 228° ( x ), and the water has 
gained 22° ( 2 ). Therefore, if water was 228, the specific heat 
of copper would be 22, for the water gained only 22, while the 
copper lost 228 The number of water is, however, 1,000 ; 
therefore, the specific heat of copper must be represented by 
0*096, which is obtained by the following proportion : 

228 : 1,000 : : 22 : 0.096. 

55. The power of different bodies to receive more or less 
heat, in rising to a given temperature, is called capacity for 
heat; it differs from specific heat in this —capacity is the 
power to receive , specific heat is that received , and these differ 
in different bodies. Thus in the experiment with the tumblers 
(52.) the space between the marbles in the first, would repre¬ 
sent capacity, and the sand which was poured in specific heat ; 
in the second, the space between, the pebbles would represent 
capacity, and the sand, as in the first case, specific heat. As 
the space and sand were less in the second than in the first, so 
capacity and specific heat are less in some bodies than in 
others, but in all cases correspond with each other, being 
greater in the same bodies, and less in the same bodies. 

56. If the capacity of bodies, for heat is in any way in¬ 
creased, a corresponding amount of cold is produced. This 
increase, or diminution of capacity, may be produced by in¬ 
creased or diminished pressure. In the mines of Chemnitz in 
Hungary, a column of water 260 feet high presses on a quan¬ 
tity of air in a tight reservoir. The pressure, therefore, is im¬ 
mense, being equal to 68 or 69 atmospheres, and when a pipe 
communicating with the reservoir of condensed air is suddenly 
opened, it rushes out with extreme velocity, instantly expands, 
and, in so doing, absorbs so much heat, that the moisture 
which it holds is precipitated in the form of snow. In this 
case, the capacity of the air for heat was diminished by the 
condensation in the air chamber. Watery vapor, therefore, 


55. How is capacity for heat defined? How does it differ from specific 
heat ? How is this difference illustrated ? 

56. What is the effect of increasing the capacity of bodies upon their tem¬ 
perature ? How may an increase or diminution of capacity be produced ? 
How is this shown in the mines of Chemnitz ? Why is the temperature of 
high steam less than that of low steam, when set free ? Is high or low steam 
more economical ? Why is not high steam generally employed ? 



GENERAL PRINCIPLES AND LAWS. 


39 


remained suspended in this condensed air without loss of heat. 
But the moment that the pressure was removed, the capaci¬ 
ties of both the air and the watery vapor for heat were vastly 
increased, both of which would lose in sensible heat, in pro¬ 
portion as they gained in capacity, and thus the vapor, and 
the jet of water would he frozen, the former in the form of 
snow, the latter in that of ice. 

When steam issues from great pressure it does not scald as 
at common pressures, although its temperature while under 
pressure was much higher than 212°. When set free, its ca¬ 
pacity is so suddenly enlarged as greatly to lower its tempera¬ 
ture or sensible heat. The diminished capacity for heat of 
steam under great pressure, renders it more profitable to em¬ 
ploy this kind of steam, or high steam , than steam at low 
pressure, or low steam. Still the latter is generally preferred, 
being less liable to accident. 


57. On'the other hand, by sudden condensation, 
a great degree of heat may be produced. Fire may be 
produced by the sudden condensation of air. In Fig. 
18. a is a piston moving air tight in a cylinder, b. On 
the end of the piston there is a cavity, in which a piece 
of tinder is fastened. When the piston is suddenly forced 
down, the condensation of the air causes so much heat 
as to set the tinder on fire. Before better means of 
obtaining fire were found out, these instruments were 
used for that purpose. 

58. The quantity of heat which bodies contain, as in¬ 
dicated by the thermometer, is called their temperature. 


Fig. 18. 
^ 5 * 


L 


This 


The temperature 


Fig. 19. 


term, therefore, applies only to sensible heat, 
of bodies cannot be accu¬ 
rately determined by our 
sensations. This may be 
shown by the following 
experiment— a, b, and c, 

(Fig. 19.) are three bowls, 
of which, a is filled with 
hot water, b with water 
at the common tempera¬ 
ture, and c with cold 

water. If the left hand be placed in a, and the right hand in 
c, and, after some time, both hands be removed to b, to the left 
hand, the water in b will appear cold, but to the right hand it 
will appear warm, or even hot. 



57. What is the effect of-dimiuishing the capacity of bodies ? Explain Fig. 18. 

58. How is temperature defined ? Explain Fig. 19. 













40 


ELEMENTS OF CHEMISTRY. 


59. A good conductor, as a metal or a stone, appears much 
colder than a bad conductor, as a brick, or dry wood. A day 
in winter, when the thermometer is at 50°, feels warmer to us 
than one in summer when the thermometer is at 60°. In 
judging, therefore, of the amount of heat in bodies at common 
temperatures, we use the thermometer, and in measuring 
intense heat, the pyrometer. From these instruments we 
learn,— 

(1.) That all bodies in the same vicinity , and not exposed 
to the direct rays of the sun, are maintained continually at 
the same temperature. Those also which are in the direct 
sunlight, as soon as the sun’s rays have left, are reduced to the 
same temperature with other bodies, and the temperature of 
distant regions is rendered more equal by currents of air, and 
oy radiation and reflection of heat. 

(2.) The range of temperature of the atmosphere is ex 
ceedingly small, compared with the extremes of heat and cold, 
which have been obtained by artificial means. More than 
25,000 degrees have been estimated, from the greatest cold to 
the highest heat yet obtained, and it is in the power of the 
chemist, by means of instruments to be described hereafter, to 
produce a heat vastly more intense than this. Yet the range 
of atmospheric temperature hitherto discovered, is less than 
200°. The greatest heat hitherto discovered, in a situation 
completely protected from the sun’s rays, is that by Belzoni, 
in a cave in Egypt, where the thermometer rose to 120°. 
The greatest cold was observed in Siberia, where the ther¬ 
mometer sunk to 70° below zero. One hundred and ninety 
degrees, we may therefore receive as the entire space occupied 
by natural heat in the scale of temperature. Much less is the 
range which man can endure with comfort, or with prolonged 
life. Many of the islands of the sea, do not differ but 20 de¬ 
grees in the entire year, and sometimes not more than 10 de¬ 
grees. 

60. The most important circumstances affecting our sensa¬ 
tions of temperature, are the following : 

m (1.) A dry air feels much cooler than a moist air at the 


59. By what two instruments is the amount of heat in bodies measured ? 
What is said of the temperature of bodies in the same vicinity ? How does 
the whole range of natural temperature compare with the extremes of heat and 
cold obtained by artificial means ? How many degrees of heat have been esti¬ 
mated from the greatest cold to the highest heat yet obtained ? What is the 
range of atmospheric temperature hitherto discovered ? What is the greatest 
heat ?—the greatest cold 1 

60. What is the first cause which affects our sensations of temperature ?__ 

the second ?—the third ? Why does clothing enable us to endure the severity 
of the winter ? How is the welfare of man consulted in the different seasons I 



GENERAL PRINCIPLES AND LAWS. 


41 


same temperature, because it cools us by evaporation of mois¬ 
ture from the surface of the body. A moist air being already 
charged with vapor, checks the evaporation from the surface, 
and thus appears to be much warmer than it really is. 

(2.) Good conductors of heat, feel much colder than non¬ 
conductors, because they carry off heat more rapidly from 
the system. Thus an iron knob feels much colder than a 
wooden or glass handle. Jewellers in this way at once dis¬ 
tinguish jewels from imitations, by touching them to the 
tongue. The real jewel is known by its coldness. A mass of 
rock-crystal may at once be known from glass, by placing the 
hand upon it. 

(3.) A situation where the air circulates freely, is much 
cooler than are others where it is still, although the thermome¬ 
ter may indicate no difference. From all bodies that are 
warmer than itself, air in motion carries off heat more rapidly 
than still air, for new portions of air are continually brought 
into contact with the warm or heated surface. This is es¬ 
pecially true of the body, which is not only exposed to a greater 
amount of air, but loses a greater quantity of moisture when 
the air is in motion, and this increased evaporation carries off 
a great amount of heat. 

(4.) Clothing enables us to endure the severity of winter, 
by preventing the escape of our heat. The inhabitants of the 
central regions of the earth wear little clothing, and that of a 
nature to intercept but little of the heat of the body. In 
temperate latitudes, during winter, the inhabitants clothe in 
woollen garments, which confine the heat more perfectly than 
cotton or linen ; and in more northern countries, the dress con¬ 
sists to a great extent of furs, which are much better non-con¬ 
ductors than woollen garments. 

(5.) In all the seasons of the year, particular provision is 
made for the welfare of man. In ivinter, the congelation of 
great masses of ice returns to the air vast quantities of latent 
heat. As spring advances, the melting of the snow keeps 
back the too sudden return of summer. In summer, the vast 
amount of evaporation which takes place, reduces to a great 
degree the temperature of the air. Finally, in autumn, the 
condensation of vapor protracts the duration of summer, and 
retards the sudden coming on of winter. 

61. At a certain distance above the earth, we come to the 
region of perpetual frost. The loftiest mountains are covered 


61. What is the Term of Congelation ? To what two causes is the intense 
cold of the air of elevated regions owing ? 




42 


ELEMENTS OF CHEMISTRY. 


with snow, which continues the entire year, and is never 
melted. The lower limit of this region is called the Term of 
Congelation. This term varies in height in different lati¬ 
tudes, being about three miles at the equator, and descending 
to the general level of the earth at the poles. The intense 
cold of the air of these elevated regions, arises from two 
causes ;— 

(1.) The sun’s rays 'penetrate through the atmosphere with¬ 
out heating it. Even at the equator, the air is heated chiefly 
from the ground, which receives the heat from the sun, and 
communicates it, by contact , to the air. This fact accounts 
for the intense heat of deserts, where no evaporation takes 
place to cool the surface, hut the heat accumulates on the 
sands. When we ascend above the general level of the earth, 
as we leave the source of heat, the air becomes gradually 
colder, until at the height of the highest mountains we come 
to a region of intense cold. 

(2.) The air of these regions is greatly rarefied. This 
cause operates to increase the capacity of the air for heat 
(55.), and thus it absorbs heat from the mountains with 
which it is in contact, producing a temperature below the 
freezing point, on the same principle that snow is produced by 
the sudden expansion of air in the mines of Chemnitz. 


SOURCES OF HEAT. 

62. The chief sources of heat are the following : 

(1.) The Sun. (4.) Percussion. 

(2.) The interior of the Earth. (5.) Friction. 

(3.) Combustion. (6.) Mixture. 

(7.) Electricity. 

63. (1.) The sun is the great source of natural heat, and 
its place in the heavens is so adjusted, that were it any further 
removed from us, or any nearer to us than it is, “ the world 
would return to its original chaos.” The amount of solar heat 
is not accurately indicated by the thermometer, for we cannot 
place this instrument in a situation exposed to the sun’s rays, 
where it will not lose most of the heat which falls upon it, by 
radiation, conduction, currents of air, &c. Were we able to 
confine all the heat which comes to it from the sun, we should 
find that this heat greatly exceeds what we are accustomed to 
consider as its amount. By surrounding the thermometer with 


62. Mention the chief som-ces of heat. 

63. What is said of the heat of the sun ? 



GENERAL PRINCIPLES AND LAWS. 


43 


non-conductors, it has been made to rise in the sun higher 
than 237 degrees. Hence we see the reason why in warm 
countries it has been considered hazardous to venture abroad 
in the open sun at noon-day, without an umbrella or some pro¬ 
tection from the direct rays of the sun. 

64. (2.) A second source of heat exists in the interior of the 
earth. It is found, in sinking mine shafts, boring for water, 
&c., that, in descending, the temperature rises 1° for every 45 
feet, or 117° per mile. If the rise of temperature continue at 
the same rate, at the depth of less than two miles the earth 
has the temperature of boiling water ; at nine miles it is red 
hot, and at thirty or forty miles depth, all known substances 
are in a state of fusion. We are standing upon a crust, and 
nearly all the four thousand miles from us to the center of the 
earth, is a melted mass, which frequently pours forth lava 
from volcanoes, or rumbles in earthquakes, when it comes in 
contact with water or other substances that produce violent 
action. 

65. (3.) Combustion is the most common and diversified 
source of heat. By his control over the process of combustion, 
man has risen to his present high state of civilization. By 
this he evinces his superiority to other animals, and asserts his 
dominion over matter. Instinct has not failed to teach the 
lower animals all that their situation required,—to build dams 
according to the most perfect rules of architecture, to con¬ 
struct nests with wonderful skill, and to understand and imi¬ 
tate man in his voice and actions ; but to employ the energies 
of heat in subduing matter, in moulding metal, in excavating 
rock, and in accumulating power which nothing can resist, is 
exclusively the prerogative of man. 

The variety and beauty of combustion may be well illus¬ 
trated by pyrotechnic compositions, some of which will be found 
in the sequel ( 2 ). 

66. (4.) Percussion produces heat on a limited scale, as in 
the hammering of iron, and in the coining of money. A bar 
of metal, after it has been heated by pounding, becomes brittle, 
but recovers its malleability after being heated in the fire. 
From this fact it is inferred, that the heat which was extri¬ 
cated by hammering was combined with the metal, and was 
the cause of its malleability. In the percussion of steel and 
flint, so much heat is produced, that the particles of steel are 
set on fire, producing what is called “ striking fire with steel.” 


64. What is said of the heat of the interior of the earth ? 

65. What is said of combustion 1 

66. What is said of percussion ? 



44 


ELEMENTS OF CHEMISTRY. 


67. (5.) Friction is another familiar source of heat. Savages 
kindle fires by rubbing pieces of dry wood together, and dry 
forests are sometimes set on fire by the motion of one limb upon 
another. The sides of a ship are said to take fire by the rapid 
descent of the cable, and the axle-trees of carriages are set on 
fire by rapid motion. Two pieces of ice have been melted by 
friction against each other in a vacuum at 32°. The water in 
which cannon are bored is sometimes heated to the boiling 
point by the friction of the borer against the metal which it 
cuts. All machinery, therefore, where there is much friction, j 
must be moistened or lubricated to diminish the heat. Dis- ; 
astrous consequences often ensue from inattention in this re¬ 
spect. 

The heat excited by friction may be classed as an effect of 
condensation, since the surfaces exposed to friction are sub¬ 
jected to constant compression. This heat is not in proportion 
to the hardness and elasticity of bodies, for a piece of brass 
rubbed with cedar wood produces more heat than when rubbed 
with another metal, and the heat is still greater when two 
pieces of wood are rubbed together. 

68. (6.) The mixture of two or more substances which act 
chemically upon each other, is almost always attended with a 
change of temperature ( 3 ). In all these cases, where heat is 
evolved, the mixture occupies less volume than the components, 

and the heat is owing to this condensation. In mix¬ 
ing sulphuric acid and water, the condensation may be • 
made apparent by the method represented in Fig. 20. a 
is a tube with a double globe. The stem and one bulb is 1 
filled with strong sulphuric acid, and the upper bulb 
with water. It is now corked and inverted. The 
water rises to mingle with the acid, and the diminu¬ 
tion of volume will be seen in the tube. Alcohol may 
be used instead of sulphuric acid, but in this case the 
tube and lower bulb are first filled with water, and the 
upper bulb with alcohol. In dissolving salts, which 
contain a large amount of the water of crystallization 
in their composition, this water is set free, and the 
volume is thus considerably increased. The solution 
of these salts, therefore, produces cold, and this is one 
cause of the cold produced by freezing mixtures ; but 
if these salts be previously deprived of their water, by exposure 
to heat, and then dissolved, heat is produced, because they 


Fig. 20. 



67. What is said of friction 1 

68. What is said of mixture ? Explain Fig. 20. 






GENERAL PRINCIPLES AND LAWS. 


45 


combine with a portion of the water, and the volume of the 
two becomes condensed. 

69. (7.) Electricity affords the means of exciting a heat as 
powerful as any that is known. The particular mode in which 
this is effected will be described hereafter, under the head of 
galvanism. 


LIGHT. 

70. This subject must be studied chiefly under natural 
philosophy, which takes cognizance of the mechanical means 
by which it is decomposed, its laws, which are chiefly me¬ 
chanical, and the phenomena that are produced by these 
laws. A few of the leading facts and properties of light only 
belong to chemistry. Among these are : 

(1.) Its composition. Light is not a simple substance , but 
is made up of three kinds of rays. These three kinds are 
called the calorific (Latin, color , heat,) or heating rays ; the 
colorific, or coloring rays ; and the chemical rays. In every 
beam of light these three lands of rays are united. The col¬ 
orific rays are found to be seven in number, viz. : violet, indigo, 
blue, green, yellow, orange, and red. The method of decom¬ 
posing light is entirely mechanical, and therefore belongs to 
natural philosophy.* 

(2.) Light produces on many bodies true chemical effects , 
causing an entire change of properties. It will be seen here¬ 
after, that two gases, chlorine and hydrogen, combine at com¬ 
mon temperatures only under the influence of light ; and when 
the direct rays of the sun fall upon their mixture in a glass 
bottle, they unite with explosion sufficient to burst the bottle. 
The chemical action of light is essential to both the animal and 
vegetable kingdom. In the animal kingdom the effect is most 
apparent in changing the color to a darker shade. When per¬ 
sons are secluded from the light, they become pale and sickly ; 
when sufficiently exposed to the light, they assume a ruddy 
and healthful complexion. Certain animal substances, how- 

- * See Olmsted’s Natural Philosophy, where many new and beautiful exper¬ 
iments illustrating the composition of light are described. 


69. What is said of electricity? 

70. What is said of the composition of light ?—its chemical effects ? What 
4re some of the effects of light in the animal kingdom ?—in the vegetable king- 




46 


ELEMENTS OF CHEMISTRY. 


ever, are bleached by exposure to the light. Thus the hair 
of children is rendered white by playing in the sun, candles are 
whitened by hanging at the windows. Bees’-wax is bleached 
by the combined action of moist air and solar light, which de¬ 
stroy both the odor and the color of the yellow wax. Oil is 
clarified by light, and woollen studs are faded or bleached by 
a similar process. 

The vegetable kingdom exhibits the effects of light in a 
much higher degree. Plants that grow in the shade are 
slender, pale, and sickly, destitute of taste, odor, and all their 
peculiar properties. When a vegetable grows in a dark place 
near a wall, if a small opening be made in the wall, the plant 
will turn towards it, make its way out, change its sickly hue to 
a lively green, and speedily acquire all its characteristic prop¬ 
erties. If to that portion which still remains in the dark a 
light be supplied from a lamp, the same effect will take place 
upon this as upon that portion without the wall, exposed to 
daylight. On this principle gardeners secure celery and cab¬ 
bage from the light, to give them tenderness and whiteness. 
The potato exposed to the light, becomes green, rigid, and bit¬ 
ter, but when grown in the dark there is produced in the long 
pale shoots a very poisonous body called solanine. Rose bushes 
that bear red roses in the light, bear white roses when made 
to grow in the dark. 

The art of Daguerreotyping depends on the chemical agen¬ 
cies of light. This process will be described hereafter, when 
the substances which are employed in it are understood. 

(3.) Light from different bodies differs in color. The white 
light of burning charcoal is the principal source of the light 
from candles, oils, and the illuminating gases, for it is the carbon 
which these flames contain that burns in the light, and gives 
intensity to the flame. This light, when analyzed, gives only 
three of the primary colors, red, yellow, and green. The daz¬ 
zling light emitted by lime, in the Drummond-light, produces 
the prismatic colors almost as brightly as the sun. The light 
emitted by iron at a dull red heat, consists chiefly of the blue 
and red rays. It is also a fact of great interest, that, while 
our sun gives white light to the bodies of the planetary system, 
there are stars or suns of different colors, which illumine the 
worlds upon which they shine with different colored light at 
different times. These stars are called' double stars. = The 


dom ? What is said of the light from different bodies ? How many of the 
primary colors are contained in the white light of burning charcoal ? How 
many in the Drummond-light? Of what does the light emitted by iron, at a 
dull red heat, chiefly consist? What is said of the.light of double stars? 



GENERAL PRINCIPLES AND LAWS. 47 

colors of two stars which together form a double star, are such 
that when united they form white light. 

(4.). All bodies emit light at a high heat , and many at the 
ordinary temperature. When the temperature of solid sub¬ 
stances is raised to about 1000°,* they begin to be luminous in 
the daylight. It requires a far higher temperature to render 
a gas visibly ignited. This may he illustrated by holding a 
piece of platinum-wire in the current of air which rises from 
a spirit-lamp ; the air is not visibly ignited, but the wire 
instantly becomes red-hot. Many bodies phosphoresce, or give 
out light at the ordinary temperature. The diamond, when 
slightly heated, rubbed, or compressed, emits a light almost 
equal to that of the glow-worm. A variety of the sepia, 
found in the Mediterranean and Indian seas, is said, when 
opened, to exhibit so brilliant a light as to illuminate a large 
room. The follo'wing fluids were found by Dr. Brewster to be 
phosphorescent when poured into a cup of heated iron ;—albu¬ 
men (white of an egg) diluted with water, isinglass in solution, 
saliva, soap and water, solution of rhubarb, of common salt or 
of nitre, tallow, alcohol, oil of dill-seeds, and oil of cloves. 

Several plants have been observed to be luminous in the 
dark. But the finest example of phosphorescence is that of 
the ocean. Here the waves that surround the ship are illu¬ 
minated, as far as the eye can reach, with innumerable bright 
spots of light rising to the surface and again disappearing, like 
a host of small stars dancing and sparkling on the bosom of the 
sea. Sometimes, also, large globes of fire are seen, mostly at 
a great depth, shining through the water, then rising rapidly 
to the surface and flashing a bright spark of light, so brilliant 
as almost to dazzle the eye, and again they float along, disap¬ 
pearing gradually with the dark water in the distance. All 
this light comes from animalcules, for, after being caught in 
vast numbers, they have continued to give out light. 

* There is considerable difference in the temperature of ignition among solid 
bodies. Metals generally become luminous at a lower temperature than other 
bodies. 


What takes place at a high heat in all bodies, and at the ordinary temperature 
in many ? What is said of the ignition of gaseous bodies 1 Mention some ex¬ 
amples of phosphorescent bodies. 



48 


ELEMENTS OF CHEMISTRY 


GALVANISM. 

ELECTRICITY OF CHEMICAL ACTION. 

71. Common electricity and magnetism are generally pro¬ 
duced by mechanical means, and therefore belong to natural 
philosophy. Galvanism, including electro-magnetism, is gen¬ 
erated by chemical agency, and therefore comes under chem¬ 
istry. 

In the year 1790, Galvani, a professor at Bologna, in Italy, 
observed that the freshly prepared legs of a frog,were convulsed 
the moment they were brought within the influence 
Fig. 21. 0 f a powerful electric machine in action. From this 

f experiment arose the science which, after Galvani, 
p is called galvanism, by means of which the constitu¬ 
tion of the crust of the 
earth has been deter- Fig. 22. 

mined and the science 
of chemistry has been 
revolutionized, 
j 72. This primitive 
experiment may be 
shown by the apparatus repre¬ 
sented in Fig. 21. Strips of two 
different metals, one silver and 
the other zinc, are made to grasp 
the thigh of a grasshopper recently 
killed. One of the metals is curved 
above, and when this is brought 
into contact with the other metal, 
the leg of the grasshopper is ex¬ 
tended, and again contracts on 
separating the metals. 

When the same apparatus is 
applied to the thigh of a frog, as 
in Fig. 22, and the two metals 
are brought into contact, the legs 
of the frog are thrown out into the 
position represented by the dotted 
lines. When introduced into a 
tumbler of water containing a 


71. From wliat experiment did the science of galvanism commence ? When 

was this experiment discovered ? 

72. Explain Fig. 21.—Fig. 22.—Fig. 23. 













GENERAL PRINCIPLES AND LAWS. 


49 


Fig. 23. 



Fig. 24. 


leech or small fish (Fig. 23), if the metals are 
brought on each side of the animal, and their 
contact above completed, the leech or fish is in¬ 
stantly disturbed, and endeavors to escape from 
its position in the course of the current. 

73. Volta, a pupil of Gralvani, first attributed 
these phenomena to their true cause—the contact 
of different metals. On this principle he ar¬ 
ranged a series of two different metals, as repre¬ 
sented in Fig. 24, with cloths wet with a saline 
or acid solution between them. In this arrange¬ 
ment the copper, c, and the zinc, z, alternate, 
and between the metals are pieces of cloth or 
pasteboard, and the pile comences with z, or zinc, 
and ends with c, or copper. On connecting the 
wires at the two ends, a current of electricity 
flows in the direction of the arrows. If the wires are sepa¬ 
rated, and one hand be placed on one end of the 
pile, and the other on the other end, a shock will 
be felt. This apparatus is called, after its inventor, 
the Voltaic pile. 

74 The discovery of Volta was announced in 
1800. Since that time other forms of apparatus 
have superseded this pile, and yet the principle on 
which they are constructed has remained the same. 

This principle is, that ivhen two dissimilar metals 
are brought into contact with an acid , or saline 
solution , a current of electricity is produced. The 
simplest illustration of this principle is made by two slips of 
metal, z and c, (Fig. 25,) one of zinc, and the 
other of copper, and a glass of acid water. If 
z and c be placed in the solution, as long as 
they do not touch each other no action is excited. 

But if they are brought into contact at the top, 
then a current is established in the solution from 
z to c, in the direction of the arrow a, and out of 
the solution in the direction of the arrow, b. The 
current may be considered as starting from z, 
passing to c, in the direction of the arrow a , as¬ 
cending c to the point where the two metals 




73. Who first attributed these phenomena to their true cause ? Explain 
Fig. 24. 

74. When was the discovery of Volta first announced ? What is said of the 
galvanic apparatus made since that time ? What is the principle of all these 
forms of apparatus? Explain Fig. 25. What is the effect of amalgamating 
zinc 1 


3 


























50 


ELEMENTS OF CHEMISTRY. 


touch each other, and then descending z to the point from 
which it started. The metal, z is usually amalgamated with 
mercury , which has the effect of counteracting any impurities 
which may he present. These impurities cause the different; 
parts of the zinc to be dissimilar, and hence much of the gal¬ 
vanic action is expended between these dissimilar portions of 
the zinc plate, and so much is taken from the current which 
passes to the copper, and through the entire circuit. Amal¬ 
gamation with mercury renders the surface more uniform, and 
thus increases the current which goes from the zinc to the 
copper. 


Fig. 26. 


75. If z and c be placed in an upright po¬ 
sition, as in Fig. 26, then there will be no 
communication, and the current will not flow 
until they are united by two wires, as w, w, 
which are soldered to each of the metals z and 
c. When the wires touch, the communication 
is completed, and the electrical current be¬ 
gins to flow. The plate of zinc, z, is called 
the zinc, or negative pole , and the copper 
plate, c, the copper or positive pole of the 
battery. These terms are continually referred 
to in describing galvanic processes, and, therefore, should be 
thoroughly understood. 



Fig. 27. 


76. To render the effects of gal¬ 
vanic action more powerful and 
striking, galvanic batteries have 
been constructed. These batteries 
are only a combination of plates of 
two different metals, on the same 
plan of alternation of metals, but 
differing from each other in form. 

One of these batteries, first con¬ 
structed by Dr. Hare, of Philadel¬ 
phia, is called the dejiagrator, from 
the energy with which it defla¬ 
grates or bums the metals and other 
combustible substances. This form 
of battery is represented in Fig. 27, 
where a single coil of zinc rests 'on the exterior cylinder of 
copper, by three wooden supports. The interior cylinder is 



75. Explain Fig. 26. What is the zinc, or negative pole, in this figure ?— 
copper, or positive pole ? 

76. What are galvanic batteries ? What is their design ? What is the bat¬ 
tery represented in Fig. 27, called ? Describe this battery. 








































GENERAL PRINCIPLES AND LAWS. 


51 


also of copper. Great power is obtained in batteries of this 
form by multiplying the coils of copper and zinc. In a battery 
constructed for Yale College, there were nine hundred mem¬ 
bers, or pairs, of copper and zinc. A great variety of effects 
may be produced by this battery, of which one of the most in¬ 
teresting is the burning of charcoal points, where an arch of 
flame of the brightness of the sun is formed, sometimes six 
inches in length. 

77. Among the effects of galvanic batteries, are the follow¬ 
ing : 

(1.) While the zinc of a battery in action is corroded , the 
capper is not acted on in the slightest degree. This fact 
proves that the origin of galvanic action is the unequal corro¬ 
sion of metals by a common fluid. The design of employing 
different metals in the construction of batteries, is to favor this 
unequal corrosion. 

In whatever manner two dissimilar metals are united, this 
unequal corrosion will take place when they are immersed in 
an acid solution. Thus, if a plate of copper be fastened by any 
method to a plate of zinc, and both be plunged in an acid mix¬ 
ture, the zinc will be corroded more rapidly from its union 
with the copper, than it would have been alone, while the 
copper will not be acted on by the fluid. Iron may in this 
way be protected from corrosion. If a polished plate of iron 
be attached to a plate of zinc, and immersed in a weak solu¬ 
tion of hydrochloric acid, the iron will remain untarnished, 
though if plunged alone in the dilute acid, it will be acted on 
immediately. On this principle is founded the method of 
galvanizing iron . Iron is covered with a coating of zinc, and 
as long as a particle of the zinc remains, the iron will not be 
acted on. Hence galvanized iron is of great use in covering 
objects which are exposed to the weather, and in other situa¬ 
tions where common iron would soon be rusted. 

The copper sheathing of ships might be protected in the same 
way ; but the gradual corrosion of the copper is found neces¬ 
sary to prevent barnacles , and other animals of the sea, and 
sea-plants from fastening to the bottom and sides of ships, and 
impeding their progress. This principle is, however, applied 


77. What is the first of the effects of galvanism mentioned ? What is the 
origin of galvanic action ? W^hat is the design of employing different metals 
in the construction of batteries 1 W'hat effect will be produced on a plate ot 
zinc, if it is united with a plate of copper, and both are plunged in an acid 
solution 1 How may an iron plate be protected from corrosion ? In what way 
is galvanized iron prepared ? Where is galvanized iron employed . WJy is 
not the copper sheathing of ships protected in this way ? What kind of boats 




52 


ELEMENTS OF CHEMISTRY. 


to the manufacture of life-boats, which are made of galvanized 

That galvanic action is produced by unequal 
corrosion is shown by the arrangement represented 
in Fig. 28. A is a jar filled with nitrate of cop¬ 
per to a, and then with dilute nitric acid to b. 
C D is a slip of copper which is immersed in both 
solutions. The part C is dissolved by the nitric 
acid, but the part D being in the solution of nitrate 
of copper, is not acted on. This unequal action 
causes a current to flow from C to D, which de¬ 
posits metallic copper at D, as will be explained 
more fully hereafter. 

As tin is not as easily acted on as iron, in tinned 
iron, or tin plates, the iron corrodes faster, because it is united 
with the tin ; but the tin being on the outside, the action can¬ 
not take place except where it has been worn off, or the iron 
uncovered in some other way, as around nails that are driven 
through the tin, or on the edges. 

78. (2.) Ignition may be performed, in a splendid manner 
by a powerful galvanic battery. On connecting the ends of 
such a battery by fine metallic wires, these conductors become 
intensely heated and emit a vivid white light. 

79. (3.) Combustion .—If the wires be sufficiently fine, or 
the communication be made by means of metallic leaves, the 

metals burn with vivid scintilla¬ 
tions. This is represented in Fig. 
29, where a piece of leaf metal 
(gold leaf, silver leaf, tin foil, &c.) 
is attached to the positive wire, p, 
and the negative wire, n, is con¬ 
nected with a metallic cover* which 
has been brightened, for the time, 
with mercury. When the leaf metal is brought into contact 
with the polished surface, it bums with a vivid light. Gold 
emits a vivid white light, inclining a little to blue ; silver, a 
vivid green ; zinc, a bluish white flame. If the galvanic cur- 

* Like the tin covers which are made for glass jars. 


Tig. 29. 



copper. 


Fig. 28. 



are made of galvanized copper ? Explain Fig. 28. What is said of the cor¬ 
rosion of tinned iron, or common tinned plate ? 

78. What is the second effect of galvanism ? How is ignition by galvanism 
performed ? 

79. What is the third effect of galvanism ? How is this produced ? Explain 
Fig. 29. What light is obtained from the combustion of gold ?—silver ?—zinc ? 
What effect is produced when the galvanic current is made to pass through 









GENERAL PRINCIPLES AND LAWS. 


53 


rent be made to pass through gunpowder, phosphorus, or a 
mixture of hydrogen and oxygen gases, they are inflamed. 
Alcohol, ether, and turpentine, may be inflamed in a similar 
manner, or by suddenly breaking the contact of the wire with 
the fluid, while the galvanic current is passing. 

80. (4.) Decompositions are produced by galvanism. If 
the ends of two platinum wires, connected with the battery, 
are placed in water slightly acidulated to improve its conduct¬ 
ing power, a stream of gas will be seen to rise from each. If 
now glass tubes, as two large test tubes of equal size, are 
placed over the wires where the gas is rising, they will collect 
this gas. One tube will be found to collect twice as much as 
the other, and on examining the gas in this tube it will be 
found inflammable, while that collected in the other tube will 
not be inflammable, but will support combustion with great 
energy. From these different properties of the two gases, one 
is known to be hydrogen, and the other oxygen ; both of which 
will be described hereafter. The inflammable gas or hydrogen, 
in water, is found by this method to be twice in volume , the 
supporter of combustion, or the oxygen. 

Galvanism is one of the most important agents of decompo¬ 
sition which the chemist possesses, and by this he is enabled 
to investigate the composition of a large class of bodies with 
great facility. 

81. In all cases of galvanic decomposition, one of the ele¬ 
ments of the body undergoing decomposition is found at the 
negative pole, and the other at the positive pole of the battery. 
In the decomposition of water, for example, the oxygen is 
found at the positive pole and the hydrogen at the negative. 
Bodies are, therefore, classed into electso-positive, or those 
which go to the negative pole of the battery, and electro-nega¬ 
tive, or those which go to the positive pole of the battery, the 
poles being supposed to attract bodies of opposite electricities, 
as in all other cases of electrical attraction. 

The terms electro-positive and electro-negative are for the 
most part relative, for most substances are electro-positive 
with regard to one class of bodies, and electro-negative with 
regard to another class. Oxygen, however, is always electro- 

gunpowder, phosphorus, or a mixture of hydrogen and oxygen gases ? How 
may alcohol, ether, and turpentine, be inflamed ? 

80. What is the fourth effect produced by galvanism ? In what way may 

water be decomposed by the galvanic current'! W^hat will arise from its de¬ 
composition ? Ans—Two gases. How wilf these gases compare with each 
other in properties ?—in volume? * 

81. What are electro-positive bodies ?—-electro-negative bodies J Why are 
these terms chiefly relative ? What body is always electro-negative ? W^hat 
are all other bodies with regard to oxygen ? 



54 


ELEMENTS OF CHEMISTRY. 


negative ; all other bodies are, therefore, electro-positive with 
regard to oxygen ; that is, when their compounds with oxygen 
are decomposed, they are found at the negative pole of the 
battery, while oxygen is found at the positive pole. 

82. When metallic solutions are decomposed the metal is 
deposited on the negative pole. This is applied in the process 
of electrotyping , or the process of depositing metals by a gal¬ 
vanic current. This process may be illustrated by the follow¬ 
ing experiment. 

With the poles of the battery, connect two polished plates 
of metal, as iron or copper. Suspend these in a dilute solution 
of sulphuric acid. If the battery is in operation it will be seen 
that one of the metals will be tarnished almost instantly, 
while the other plate remains bright. This must be owing to 
a different action on the two * plates, for both are in the same 
solution ; the acid acts on one and does not act on the other. 
The one that is acted on will be found to be always the one at 
the positive pole, and the plate not acted on the one at the neg¬ 
ative pole. The action of the sulphuric acid on the plate at 
the positive pole, if of copper, produces sulphate of copper, if 
of iron, sulphate of iron, as will be shown hereafter. This is 
dissolved in the solution, and when the latter in this way be¬ 
comes charged, then a new operation will be observed. Me¬ 
tallic copper will begin to be deposited on the plate at the neg¬ 
ative pole, the plate which hitherto had been unaltered. 

By this process a solution of sulphate of copper has been 
formed, but it is usual to commence with making the solution 
by dissolving the salt itself. Then, on immersing the two 
poles of the battery in the solution, a deposition of metal takes 
place at once ; at the same time, as in the former case, the 
metal at the positive pole is continually dissolved. The metal, 
therefore, at this pole is changed into sulphate of copper, and 
at the negative pole the sulphate of copper is changed into 


82. When metallic solutions are decomposed, where is the metal deposited ? 
What is meant by the process of electrotyping ? By what experiment is this 
process illustrated ? At which pole is the metallic plate which is acted on ? 
What does the action of the sulphuric acid on this plate produce ? What takes 
place when the solution becomes charged with sulphate of copper ? What is 
the usual method of commencing the electrotype process ? What then takes 
place on immersing the two poles of the battery 1 Why is the solution kept 
continually charged with sulphate of copper, notwithstanding this is continually 
decomposed and metallic copper deposited on the negative pole ? Ans.—Be¬ 
cause sulphate of copper is continually formed at the positive pole, as fast as it 
is decomposed at the negative pole. How is this accomplished 1 Ans.—The 
sulphuric acid which is set free by the decomposition of the sulphate of copper 
at the negative pole, travels over to the positive pole and there corrodes the 
copper wire, or plate, forming with it sulphate of copper ? When silver is to 
be plated, what solution is used ? What is placed in the positive pole ? Why 
is a piece of silver placed in the positive pole ? How is gold plated ? 



GENERA.!. PRINCIPLES AND LAWS. 


55 


metallic copper, which is deposited on the metallic plate at this 
pole, and the sulphuric acid, set free from this decomposition 
of the sulphate of copper, travels over and attacks the plate at 
the positive pole. Thus the latter plate becomes continually 
smaller, while the plate at the negative, pole is continually in¬ 
creased by fresh depositions of metal. The solution is kept 
charged with sulphate of copper as long as the copper plate at 
the positive pole remains. All other metallic depositions by 
galvanism are made on the same principle. If copper is to be 
deposited, a solution of a salt of copper is employed, and a 
piece of copper at the positive pole to keep up the strength of 
the solution. If silver is to be plated, a silver solution is em¬ 
ployed, and a silver coin or other piece of silver is placed in the 
positive pole. To plate gold, in like manner, a solution of gold 
is used with a pieee of gold at the positive pole.( 4 ) 

83 (5.) Magnetism is produced by galvanic action. Elec¬ 
tro-magnetism has recently grown almost to a distinct science 
of great interest and great importance, particularly in its ap¬ 
plication to the Electric Telegraph. As the principle of the 
telegraph and its different varieties are fully described in natural 
philosophy,^ it will not be necessary to repeat that description 
in this work, although this instrument has relations also to 
chemistry. As its construction and mode of action are entirely 
mechanical, it is allied to natural philosophy ; as the galvanic 
fluid by which it is put in motion, is generated by chemical 
agents, it might be described under chemistry.( 6 ) 

84. The different forms of galvanic batteries are found to 
produce very different results. If we take a square foot of 
copper and a square foot of zinc and place a wet cloth between 
them, we shall have a battery which cannot give shocks nor 
decompose water, but which will cause a fine metallic wire 
to become white hot, and even to fuse. If again* we take a 
square foot of copper and another of zinc, and cut each into 
144 plates an inch square, and arrange them with similar 
pieces of cloth, as in the Voltaic pile, the instrument will give 
shocks and decompose water rapidly. From the same quantity 
of metal, therefore, two species of battery may be made ; one 
consisting of a few plates with a large surface, and the other 
of a great number of small plates, or plates with small surface. 

* Olmsted’s Natural Philosophy. 


83. What is the fifth effect of galvanism ? 

84. What is said of the different forms of galvanic batteries ? What are 
quantity batteries ? What effects do they produce ? What are intensity bat¬ 
teries ? For what effects are these batteries adapted ? To which class does 
the deflagrator belong ? 



56 


ELEMENTS OF CHEMISTRY. 



The former produce greater magnetic and heating effects, and 
are called quantity batteries ; the latter are more powerful in 
giving shocks, decomposing water, &c., and are 
Fig. 30. called intensity batteries. The deflagrator, 
already described (76.), is an example of the 
first kind of battery. 

85. Smee's battery (Fig 30.) is an example 
of the second. It consists of a plate of platin¬ 
ized silver, or platinized* platinum, S, on each 
side of which are placed parallel plates of 
amalgamated zinc, ZZ. w is a strip of wood 
long enough to extend over the rim of the 
tumbler. To this strip of wood the zinc plates 
are firmly attached by means of a metal clamp. 
One of the poles, Z, rises from this clamp and 
is therefore connected with the zinc plates by 
a metallic communication. The other pole, 

, passes through the wood and is connected with the silver. 

The wood serves to insulate the two poles from each 
Fig. 31. other. These poles have screws for attaching wires. 

86.- Groves battery , a section of which is exhibi¬ 
ted in Fig. 31, is employed where great power and 
intensity are required. Z is the cylinder of zinc ; 
c is a cup made of porous earthenware ; p is a strip 
of platinum. The porous cup is filled with strong 
nitric acid and into this the platinum is placed. The 
glass cup a is filled with dilute sulphuric acid and the 
cylinder of zinc is let down into the sulphuric acid. 

To use this battery, first fill about half 
full the glass cup or tumbler, a, and let Fig. 32. 
down into the solution the zinc cylinder. 

Within the zinc cylinder let down the 
porous cup containing nitric acid. This 
will cause the sulphuric acid to rise, so as nearly 
to fill the tumbler. Finally, place in the nitric 
acid the strip of platinum, connect the poles, and 
the galvanic action will commence. 

87. Daniel's battery is another common form of 
the galvanic battery. It consists of a copper cylin¬ 
der c, (Fig. 32.) into which a solution of sulphate of 
copper is poured. Within this is a second cylinder, 

* Plates on which platinum is precipitated in the form of a black powder. 



85. To which class does Smee’s battery belong 1 Explain Fig. 30. 

86. Explain Fig. 31. How is Grove’s battery prepared for use ? 

87. Explain Fig. 32. 




































GENERAL PRINCIPLES AND LAWS. 


57 


p, of porous earthenware filled with dilute sulphuric acid, into 
which an amalgamated zinc rod, z, dips. From the copper 
and. zinc projects rods, r, r, terminated in binding screws by 
which the polar wires may be connected. 

88. Each dne of these batteries has its peculiar advantages, 
and the object to be accomplished determines which one shall 
be employed. With the deflagrator, Grove’s and Daniel’s, all 
can be accomplished that is desired ; the deflagrator for mag¬ 
netic purposes, Grove’s for chemical decompositions, and Dan¬ 
iel’s for gilding and electrotype purposes. If, however, only 
one can be purchased, Grove’s is to be chosen on account of its 
varied uses. 


LAWS OF CHEMICAL AFFINITY. 

89. (1.) Affinity acts universally upon bodies. For this 
reason none are isolated, but every body has relation to other 
bodies by which it is surrounded, and is capable of entering 
into combination with them.( 6 ) 

(2.) Bodies most opposed to each other in chemical proper¬ 
ties, evince the greatest tendency to enter into combination. 
The converse of this proposition presents this principle in a 
more striking light, that bodies whose properties are most alike, 
manifest the least attraction. It will be shown hereafter that 
many of the gases, as oxygen, chlorine, iodine, &c., are very 
much alike in their properties ; these bodies have far less at¬ 
traction for each other than they have for hydrogen and the 
metals, the properties of which are totally dissimilar.( 7 ) 

(3.) As a general rule, simple bodies unite with simple, 
and compound bodies with compound. 

(4.) All solid bodies which have many pores, and conse¬ 
quently much surface, attract fluids and gases. A piece of 
charcoal the size of a walnut is intersected by many hundred 
partitions, which, if they could be placed by the side of each 
other, would cover a space a thousand times larger than the piece 
of coal itself covers. The force of attraction of this large surface 


88. Mention the peculiar advantages of the deflagrator, Grove’s and Daniel’s 
batteries. 

89. What is the first law of chemical affinity ? Whence is this law derived ? 
What is the second law of affinity 1 How is the converse of this proposition 
stated ? What is the third law of affinity ? Is this law universal 1 —Ans. 
There are some exceptions, but it is true in the great majority of cases. What 
is the fourth law of affinity ? What example is given ? What is the fifth law 

3 * 




58 


ELEMENTS OF CHEMISTRY. 


is so powerful, that the coal can absorb from 80 to 90 times its 
own bulk of many kinds of gases. It is very probable that 
these gases, by this compression into 80 or 90 times smaller 
space within the coal, become fluid or solid. 

(5.) Affinity takes place only between the minute particles 
of bodies. Two bodies which have a strong affinity for each 
other will not act on one another while in the solid mass, nor 
even in a state of fine powder, except in a few instances. If 
one of these be in solution, the action will take place readily, 
but it will be most vigorous when both the ingredients are in 
solution. Minute division, therefore, favors the action of 
affinity ; on the other hand, cohesion opposes it ( 8 ). In some 
cases it is sufficient to heat one of the solid bodies till it sof¬ 
tens ; thus iron, surrounded with charcoal and heated to 
whiteness, is slowly penetrated by the charcoal. 

(6.) Affinity takes place not only between two , but also be¬ 
tween three, four, or any number of bodies f) 

(7.) The compounds formed by affinity possess new proper¬ 
ties, different from those of the constituent bodies. Almost 
all substances we meet with furnish illustrations of this law, 
being very different in their nature and appearances from the 
elements of which they are composed. Water, our only safe¬ 
guard against fire, contains the most inflammable of all the 
elements united to the greatest supporter of combustion :—to a 
body in which even iron and other metals burn with great 
energy. Our table salt is composed of corrosive and poisonous 
ingredients, and the same elements that form nitric acid, 
which will destroy the firmest parts of the body, form also, in 
another proportion, the atmosphere we breathe. In preparing 
medicines it is unsafe to infer that the compounds will possess 
the aggregate virtues of the simples, since by the action of 
affinity, the most harmless elements sometimes form com¬ 
pounds that are corrosive and poisonous, while others that are 
most corrosive and poisonous render each other inert and 
harmless.( 10 ) 

(8.) Bodies have different degrees of affinity for each other. 
This principle is implied by the second law already given. It 
is introduced under this head for further illustration, and on 
account of its relation to the laws which follow. 


of affinity ? Mention some examples. What is the sixth law ?—seventh? 
What examples are given? What is the eighth law? What is said of the 
Strength of affinity in some cases ? How weak is it in other instances ? What 
depends upon this law ? How is this illustrated ? What illustration of double 
decomposition is given? How do the new compounds, C and D, compare 
with the first A and B ? Are single or double decompositions most powerful ? 
How is this illustrated ? What is the ninth law of affinity! How is this 



GENERAL PRINCIPLES AND LAWS. 


59 


In some cases the elements of a compound body are so 
strongly united, that they can scarcely be separated by any 
means in our power ; in other cases the union is so slight, that 
it is easily overcome, and sometimes even a spontaneous 
separation occurs. Between these extremes, attraction exists 
in many different degrees of strength. Upon this law depends 
the whole art of decomposing bodies; for when two bodies, 
A and B, are united in a compound, we have only to find a 
third body , G, which has a stronger attraction for one of them 
than they have for each other, and it will effect their separa¬ 
tion, and we shall have a new compound which may be rep¬ 
resented by A and C, B having been excluded. 

The foregoing is the simplest case of decomposition. A more 
common mode is that called double decomposition. A is 
composed of two elements ; *B is also composed of two ; to¬ 
gether there are four elements, and these elements act on each 
other independently of their previous relations to the com¬ 
pounds A and B. If numbers 1 and 2 belonged to A, and 
numbers 3 and 4 belonged to B, then 1 of A will take 3 of B 
and form a new substance C. And 2 of A will take 4 of B 
and form a new substance D. We have therefore the follow¬ 
ing formulas ;— at first 1 + 2=A ; 3 + 4=B : after double de¬ 
composition, 1 -f-3 = G ; 2 + 4=D. C and D are entirely 
different bodies from A and B. 

Double decompositions prevail where simple decompositions 
could not be effected. Thus, in the last example, unless the 
elements which we have numbered 1, 2, 3, 4, were all pres¬ 
ent, in most cases, no decomposition could be effected. It 
would appear that if 3 were uncombined with 4, or if it was 
bound by no affinity whatever to 4, that, being free, it would 
act with more energy in decomposing the compound 1 + 2 or 
A, than it would in its combined state. But this is not the 
fact. When united to 4 it may effect the decomposition of 
1 + 2 when, separately, it would not have altered this com¬ 
pound. # (“) 

* This may perhaps be accounted for in the following way. Upon the com¬ 
pound 1+2 two attractions may be supposed to operate at the same time, viz. 
that of 3 for 1 to form the new compound 1+3, or C, and that of 4 for 2, to form 
the new compound 2+4, or D. Now the sum of these attractions acts to re¬ 
solve A, or the compound 1+2, and this evidently with greater power than 
either the attraction of 3 for 1, or 4 for 2 separately, and therefore a decomposi¬ 
tion is effected by the united, which would not have been effected by the sin¬ 
gle attractions. 


illustrated ? What is the tenth law of affinity called 1 State this law. How is 
this illustrated ? What is the law of combination for compound bodies 1 What 
example is given 1 What is disposing affinity ? What is meant by the nas¬ 
cent state of bodies 1 




60 


ELEMENTS OF CHEMISTRY. 


(9.) When a body , A, combines ivith different quantities of 
another, B, all the higher proportions of B are in a simple 
ratio to the lowest. Thus if there are several combinations of 
the same bodies, A and B, and if in the first the quantity of A 
be just equal to that of B, then in the next higher it will be 
just twice, thrice, four times, &c., that of A.( 12 ) 

(10.) The most important law of Chemistry is that which 
is called the law of equivalent proportions. It may be thus 
stated : When a body , A, unites with other bodies, B and C, 
the proportion in which A unites with B and C, will repre¬ 
sent the proportion in which they will unite with each other .' 
Thus, hydrogen will unite with carbon in the proportion of 1 
to 6, and with oxygen in the proportion of 1 to 8. Therefore 
carbon and oxygen unite with each other in the proportion of 
6 to 8. 

(11.) The preceding law relates to simple bodies'; the law 
for compound bodies is the following : Add together the num¬ 
bers corresponding to the elements of the compound body ; the 
sum will represent the proportion in which the compound en¬ 
ters into combination. Thus common salt is a compound of 
chlorine and sodium. Chlorine combines in the proportion 
represented by the number 35. Sodium combines in the 
proportion represented by the number 23. Therefore the 
compound of chlorine and sodium, that is common salt, com¬ 
bines in the proportion represented by 35 + 23, or by the 
number 58. 

(12.) A peculiar chemical action is produced by certain 
bodies which is called presence-action or disposing affinity, by 
which is meant that affinity which exists between two or more 
bodies hi consequence of the presence of another body. 

(13.) Affinity often takes place between bodies when first 
set free from their combinations by decomposition, when under 
other circumstances it does not occur. This state of bodies is 
called the nascent state.* 


Latin, nascens, arising. 


PART II. 


THE ELEMENTS AND THEIR COMBINATIONS. 




90. A vast field opens before us when we leave the general 
principles of Chemistry, for the consideration of the chemical 
relations and agencies of particular bodies. Every object in 
the material world is to be explored. Without, therefore, a 
method of great simplicity, this immense mass of facts and de¬ 
tails would be a labyrinth of doubt and obscurity. But here, 
as elsewhere, the simplicity of the laws of nature is most ap¬ 
parent where the greatest complexity might be expected. By 
a few laws of numerical exactness and simplicity, and by a 
few bodies which have not been decomposed, and are therefore 
called elements , all the objects in nature are formed, and com¬ 
binations produced without number. 

91. The elements, or simple undecomposed bodies, are 65, 
in number, and are divided into metals and non-metallic 
substances. The relations of the non-metallic substances are 
more extensive than those of the metals ; we shall therefore 
consider these first. The following is a list of these sub¬ 
stances : 


Oxygen, 

Nitrogen, 

Hydrogen, 

Carbon, 


Organogens. (Components of organic forms.) 


These four elements make up, almost exclusively, organized 
objects, both animal and vegetable. 

Sulphur, ) 

Selenium, > Pyrogens. (Fire producers.) 

Phosphorus, ) 


90. What portion of the subject of chemistry do we now leave ? Upon what 
division of the subject do we enter ? What is said of the extent of this sub¬ 
ject 1 How is the simplicity of the laws of nature illustrated in this part of 
chemistry ? 

91. What are elements ? How many elements are there ? Into what two 




ELEMENTS OF CHEMISTRY. 


G2 


These elements are distinguished by their easy combustibility. 


Halogens. (Salt producers.) 


Chlorine, 

Iodine, 

Bromine, 

Fluorine, 

These elements, by their combinations with the metals, pro¬ 
duce saline compounds, as common salt formed of chlorine and 
the metal sodium. 


Boron, 

Silicon, 


j- Hyalogens. (Glass producers.) 


These elements, united with many bases, form t]^e various 
kinds of glass. 

The relations by which these bodies are arranged under the 
four classes given above, are those by which they are best dis¬ 
tinguished from each other, although some of these bodies have 
other relations of equal or greater importance than those 
upon which these distinctions are founded. This is especially 
true in the case of the three first elements. Of these, oxygen 
and nitrogen form the atmosphere, and will be considered 
under that head ; oxygen and hydrogen form water, and 
will be described under that subject. 


THE ATMOSPHERE. 

92. Two transparent fluids form the atmosphere,—oxygen 
and nitrogen. They are called gases ; that is, they are per - 
momently elastic aeriform fluids. Many other bodies are 
elastic, but gases alone are permanently elastic, for they alone 
return to their original volume when the compressing force is 
removed, however great that force may be, or however long 
continued. 


OXYGEN. 

93. The first and most important of all gases, is oxygen. 
It is never found in a separate state, but is combined with 
several substances, from which it is obtained by the appliea- 


classes are they divided? Mention the organogens. What is meant by this 
term? Why is this term applied to these four bodies ? Name the pyrogens? 
What is meant by this term ? Why is it applied to sulphur, selenium, and 
phosphorus ? Name the halogens. What is meant by the term halogen ? Why 
is it applied to chlorine, iodine, bromine, and fluorine ? Name the hyalogens, 
and define the term. Why is this term applied to boron and silicon ? 

92. What two transparent fluids compose the atmosphere ? Why are they 
called gases ? 

93. What is the most important of all the gases? Is it ever found in a sep- 
arate state ? How is it obtained ? What is the most convenient source of oxy¬ 
gen ? Explain Fig. 33. 




THE ELEMENTS AND THEIR COMBINATIONS. 


63 


tion of heat. The most convenient of these substances is 
chlorate of potash. The process is represented in Fig. 33. 
A glass flask is fitted with a bent tube passing through a 


Fig. 33. 



cork. This tube conveys the gas beneath the mouth of an in¬ 
verted jar. ( 13 ) An ounce^ of chlorate of potash, and 48 grs. 
(y 1 ^ part) of black oxide of manganese, are well mixed and put 
into the flask. The heat from the lamp beneath soon drives 
off the gas and displaces the water from the jars, until, from a 
small quantity of the salt, quite a number of jars are filled 
with oxygen very nearly pure. Heat decomposes chlorate of 
potash by expanding its constituent particles, and thus counter¬ 
acting affinity, which is exerted only at insensible distances 
(p. 11.), and is therefore impaired or destroyed by whatever 
tends to separate the particles from contact with each other. 
The oxide of manganese which is mixed with the chlorate of 
potash acts only by its presence (p. 60) to facilitate in a very 
great degree the decomposition of this salt. Alone the chlorate 
of potash is not decomposed at a temperature less than about 
1000°, but when mixed with the oxide of manganese, or oxide 
of copper, the oxygen is evolved at a much lower temperature, 
while these oxides remain unchanged.( 14 ) 

Chlorate of potassa consists of 


Chloric acid 
and 
Potassa, 


Oxygen. # .Oxygen. 

Chlorine ' (escapes as gas.) 

Oxygen .* **' 

Potassium (metal)-—^ chloride of potassium. 

(remains in the flask.) 


* A larger quantity, as five ounces, is more convenient after some familiarity 

with the process has been acquired. 











































64 


ELEMENTS OF CHEMISTRY. 


In this and the following diagrams the body which is to he 
obtained (as oxygen in this case) is placed in small capitals. 
Unbroken lines denote solid bodies (as chloride of potassium in 
the above diagram), since in solid bodies cohesion is unbroken 
by repulsion (p. 11.) The broken lines (see diagram, art. 136) 
denote liquids, because in liquid bodies cohesion is broken , 
though not entirely destroyed by repulsion. Dotted lines de¬ 
note gases (as oxygen in the above diagram), since cohesion in 
gases is entirely destroyed by repulsion. 

94. Properties. Oxygen is colorless, and has neither taste 
nor smell. It is heavier than air in the proportion of 11 to 10. 
It unites with all the simple substances, or elements,* and 
with a vast number of compound bodies. It therefore consti¬ 
tutes a larger portion of the earth. Water contains 89 per 
cent, and atmospheric air 23 of its weight of oxygen. Com¬ 
mon water will not perceptibly dissolve oxygen, because it al¬ 
ready holds a quantity in solution ; but if the water is pre¬ 
viously boiled, and then allowed to cool in a close vessel, it 
dissolves 3|- per cent, of oxygen. 

95. Oxygen is that constituent of air which supports ani¬ 
mal life , and yet in a pure state it is deleterious to life. If an 
animal, as a mouse, be placed in a jar of oxygen, he will live 
four times as long as he will live in a jar of equal capacity con¬ 
taining common air. This is not because oxygen is a better 
supporter of life than common air, but because the oxygen of 
the jar of air is sooner exhausted than that of the other which 
contains pure oxygen. If the first jar were supplied with con¬ 
tinual portions of fresh air, the animal would live; but in the 
second jar, with fresh portions of oxygen, it will die in a few 
hours. This gas is too exhilarating, and needs to be diluted, 
as with nitrogen in common air. 

96. It is sometimes used to resuscitate life. Men and ani¬ 
mals have been resuscitated by oxygen, when all other means 
of restoring life have failed. 

97. Oxygen is that constituent of air which enables it to 
support combustion. This is proved by the fact that the pro¬ 
ducts of the combustion of all bodies weigh more than the 
bodies from which they were obtained, and this increase of 

* Except perhaps fluoiune, with which no combination of oxygen has yet 
been discovered. 


94. Mention some of the properties of oxygen. 

95. What is said of the relations of oxygen to animal life ? 

96. For what purpose has oxygen sometimes been employed ? 

97. What is said of the relations of oxygen to combustion ? What must be 
employed to commence the combustion of a body in oxygen ? In what way 





THE ELEMENTS AND THEIR COMBINATIONS. 


65 


weight is exactly that which has disappeared durirjg the pro¬ 
cess. Combustion, however, does not usually take place by 
mere contact of oxygen ; heat, light, electricity, compression, 
expansion, contact with platinum or certain other metals, or 
with a body already in the process of oxidation, must be em¬ 
ployed, according to circumstances, to produce this combustion. 
When once commenced, the action goes on usually with great 
energy, being supported by the heat generated by the combus¬ 
tion itself. The temperature required to produce the combina¬ 
tion of any substance with oxygen, is different, not only for 
different substances, but even for the same substance,—in the 
latter case producing two distinct kinds of combustion, one 
called the slow combustion , as that of phosphorus at ordinary 
temperatures, and the other the rapid combustion , as that of 
phosphorus when ignited. Charcoal also burns slowly below 
a red heat. Slow combustion often passes into rapid combus¬ 
tion, as when phosphorus is dried on a piece of filter paper and 
placed on dry cotton. Fires in ships and manufactories have 
sometimes originated in this way, from the slow combustion 
of cotton or tow moistened with oil. Charcoal, when heaped 
in masses, often takes fire in this way, and the explosion of 
powder mills has been produced from this cause. 

98. The energy with which pure oxygen can support 
combustion, may be illustrated by a variety 
of pleasing experiments. Fig. 34 repre¬ 
sents the method of burning iron in oxygen 
gas. A wire is terminated by a match of 
sulphur and thread. This is lighted and al¬ 
lowed to burn for a short time, until it be¬ 
comes heated, and then, while a little fire 
yet remains on the iron, the stopper is care¬ 
fully removed, and the wire let down into 
the jar. Instantly a blue flame is seen, 
which is that of the sulphur. As soon as 
this is burnt off, the iron takes fire, and 
burns with the most splendid scintillations. 

Globules of iron will be thrown off, which, 
if collected and weighed, will be found to 
weigh more than the iron which was consumed, on account of 
the oxygen which has combined with them. The watch- 
spring should be placed carefully in the jar, for a very small 


Fig. 34. 



does combustion continue itself? What is meant by slow combustion ?—rapid 
combustion ? Mention some examples of slow combustion passing into rapid 
combustion ? 

98. Explain Fig. 34. 







66 


ELEMENTS OF CHEMISTRY. 


portion of burning sulphur, falling on the jar, would be suffi¬ 
cient to crack it. If the experiment be made on a plate, the 
fused globules melt into the plate, after falling through a stra¬ 
tum of water half an inch thick. ( 15 ) * 

99. Ozone. This is the name of a substance, the exact 
nature of which is not well understood. It was regarded by 
Faraday as only an allotropic* condition of oxygen. Though 
found in very peculiar and widely different circumstances, it is 
never manifested except where-oxygen and water, or watery va¬ 
por, are present. It has never been isolated from the atmos¬ 
phere, but its presence in large quantity is detected by its pecu¬ 
liar smell—that which is perceived when an electrical machine 
is in action—and in minute quantity by certain chemical tests. 

Ozone may be prepared in large quantity by introducing 
pieces of phosphorus cleansed from the oxide, into capacious 
bottles (holding about 3 gallons) having glass stoppers. Into 
these bottles a small quantity of water is poured, so that the 
phosphorus is partly in, and partly out of the liquid. The 
vapor of phosphorus and phosphorous acid (158), which rises 
in a current, is absorbed by the water, and, in about ten or 
twelve minutes the ozone is produced. It is, however, now 
mixed with oxygen and nitrogen (from the air originally in 
the bottles). The bottles are inverted in the water-bath 
(Fig. 33), and the phosphorus thus removed ; after which 
fresh water is agitated in them, to dissolve the small quantity 
of phosphorous acid remaining (158). 

Ozone has very great bleaching power, in which respect, as 
well as in many others, it differs from oxygen and nitrogen. 
Several ounces of indigo solution, poured into one of the bottles 
containing ozone, and agitated, will be bleached as effectually 
as by chlorine (139). If the bottle containing it is allowed to 
remain unstopped, it soon escapes into the air. It is entirely 
destroyed by heat. When passed through a tube heated to 
130°, it entirely loses its properties. When an ozonized at¬ 
mosphere is made as dry as possible, and then sent through a 
red-hot tube, the ozone disappears, being converted apparently 
into ordinary oxygen, and no water or any other result is pro- 

* The same bodies are often found under two or more different states or 
forms, called attotropic states; thus the diamond, charcoal, lampblack, &c., are 
the same body under different allotropic forms. In one of these states bodies 
readily exert their active properties; in the other they seem passive, and as 
it were torpid. The diamond is the passive form of carbon (124), for it can 
hardly be made to burn even in oxygen gas; while lampblack is so highly 
combustible, that it often takes fire spontaneously in the open air. 


99. What is ozone supposed to be ? What are some of its remarkable 
properties ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


67 


duced. Air which is strongly charged with ozone impedes 
respiration, and produces catarrhal affections. Small animals 
are quickly killed by it, Organic coloring matter, liquors, and 
albuminous substances it quickly destroys. Ozone acts pow¬ 
erfully upon most metals, causing them to assume their highest 
state of oxidation. In this respect it is the most powerful oxi¬ 
dizing body known. This action commences at 32°. It is 
probably the great natural agent employed to convert the in¬ 
jurious exhalations which the air is constantly receiving into 
harmless substances, by oxidizing and thus destroying their 
effluvia. An atmosphere charged with ozone immediately 
deprives the most putrid solid or fluid bodies of all disagreeable 
smells. In large and populous cities, and in close and crowded 
dwellings the ozone is to such a degree exhausted by the oxi¬ 
dation of effluvia that its presence can hardly be detected. 
Faraday, on examining the air at Brighton, found that when it 
came over the town no ozone could be detected, but when it 
was received before it reached the town, the presence of ozone 
was distinctly manifested. As this body is generally formed 
during the process of combustion, and as large fires have fre¬ 
quently proved effectual in stopping the pestilence, it has been 
supposed that this was owing to the formation of vast quanti¬ 
ties of ozone. 

100. Oxides and acids. All the compounds of oxygen are 
either oxides or acids. Acids are characterized by peculiar 
properties, which will be described more fully hereafter. They 
are generally known from their sour taste and their reddening 
vegetable blue infusions. Oxides are those compounds of ox¬ 
ygen which are not acids. Thus water, in chemical language, 
is an oxide of hydrogen (87.), and does not possess acid prop¬ 
erties. The oxides are also subdivided according to the pro¬ 
portion of oxygen which they contain. Protoxide is that ox¬ 
ide which contains one equivalent of oxygen and one of the 
base with which it is combined. In some cases a smaller pro¬ 
portion of oxygen combines with the base. These compounds 
are called suboxides, by which is meant those oxides which 
have less oxygen than that which is called the prot or first 
oxide. Deutoxide contains twice as much oxygen as the pro¬ 
toxide. Sesquioxide (Latin sesqui, one and a half) is half¬ 
way between protoxide and deutoxide. Tritoxide is the third 
oxide, containing three times as much oxygen as the protoxide. 


100. Into what two classes are the compounds of oxygen divided ? How are 
acids generally known ? What compounds of oxygen are called oxides ? 
What is water called in chemical language ? W^hat is meant by the term pro¬ 
toxide—suboxide ?—deutoxide ?—sesquioxide ?—peroxide ? 




68 


ELEMENTS OF CHEMISTRY. 


Peroxide (Latin 'per, which denotes completeness) is the high¬ 
est oxide , whether that be the second if there are only two, the 
third, if there are only three, or the fourth if there are only 
four. This is also usually applied to the highest compound of 
oxygen which does not possess strongly marked acid properties. 

101. "While the oxides are thus distinguished by prefixes, 
the acids are distinguished by affixes or additions. The two 
terminations, ic and ous , are used to distinguish acids, oils de¬ 
noting the smaller proportion and ic the larger. Thus nitric 
acid contains a greater proportion of oxygen than nitrous acid, 
and sulphuric acid than sulphurous acid. ( 16 ) 


NITROGEN. 


102. If we withdraw the oxygen from a given portion of 
common air, the residue is nitrogen. A piece of phosphorus 


Fig. 35. 



about the size of a small pea is placed 
upon a little saucer of tin or iron, and 
this upon a float of cork or wood. It is 
then set on fire, and instantly a jar is in¬ 
verted over the burning phosphorus (Fig. 
35.) ( lv ). The phosphorus will consume 
the oxygen of the air beneath the bell 
glass, and the water will rise. By the 
combustion of the phosphorus, phosphoric 
acid (160) is formed, which is absorbed 
by the water in the jar, and nothing re¬ 
mains but nitrogen. 


The jar contained 


Air \ ^ itr °g en - 
( Oxygen - 

and 


•Free nitrogen. 


-phosphoric acid. 

(dissolved in water.) 


Phosphorus., 

103. Nitrogen is found in a free state in the air bladders of 
fish, and in other cavities in the bodies of animals and vege 
tables. Its properties are chiefly negative. It does not sup 
port combustion ( 18 ), or animal life. A mouse placed in a ja: 


101. In what manner are acids distinguished ? What does the termination 
ous denote ?—ic ? What examples are mentioned 1 

102. Explain Fig. 35. 

103. Where is nitrogen found in a free state ? What is said of its proper 
ties? What is its effect on combustion and animal life? In what manne 














THE ELEMENTS AND THEIR COMBINATIONS. 


69 


of nitrogen dies almost instantly. It is not poisonous, however, 
like some gases, but it destroys life by suffocation. Its affinity 
for other bodies is generally small; its compounds are there¬ 
fore easily decomposed by heat. The nitrogen is disengaged 
in the gaseous form, often with such violence, as to produce ex¬ 
plosion. 

104. Nitrogen is very widely diffused in nature, particularly 
in the organic kingdom, for we find it in all plants and animals. 
It is an essential constituent of the animal frame, and exists in 
the tissues or muscles of the body to the amount of 17 per cent. 
( 19 ) It is, therefore, abundantly contained in the food of all 
animals. The following table contains the proportion of nitro¬ 
gen in some of the most common articles of food : 


Rice, 

. . 81. 

Eggs, (yolk,) 

305. 

Potatoes, . 

. . 84. 

“ (white,) . 

345. 

Turnips, 

. . 106. 

Ham, (raw,) 

539. 

Rye, . . 

. . 106. 

“ (boiled,) 

807. 

White bread, 

100 to 125. 

Mutton, (raw,) . 

773. 

Milk, . . 

. . 237. 

“ - (boiled,) 

852. 

Peas, 

. . 239. 

Beef, (raw,) . 

880. 

Beans . 

. . 320. 

“ (boiled,) 

942. 

105. Nitrogen 

is somewhat lighter than common 

air, a: 

of course, lighter than oxygen. 

Still it is diffused through* 


the atmosphere in every part, although not chemically com¬ 
bined with oxygen. This principle of the diffusion of gases , 
may he illustrated by the following experiment :—Two flasks, 
(Fig. 36), are connected by a tube passing through their 
corks. One of the flasks contains oxygen, and the Fig. 36. 
other nitrogen. When placed as represented in the 
figure, the heavier gas, or oxygen in the lower flask, 
and the lighter or nitrogen in the upper, after remain¬ 
ing a day or two, the gases in both will be found alike, 
or, rather, each flask will be found to contain a mix¬ 
ture of oxygen and nitrogen. In this case, the nitro¬ 
gen, though the lighter gas, has descended from the 
upper flask through the tube into the lower, and the 
oxygen has ascended through the tube into the upper 
flask. This property, which gases possess of mingling 
with each other, notwithstanding their difference of specific 


does it destroy life 1 What is said of its affinity for heat ? What is said of 
the compounds of nitrogen ? 

104. Why is nitrogen an essential constituent of food ? 

105. How does the density of nitrogen compare with that of common air ? 





70 


ELEMENTS OF CHEMISTRY. 


gravity, is called the diffusion of gases. It is a principle of 
the first importance, and will therefore be explained more fully 
hereafter, when the different gases are known. It is owing to 
this principle, that the gases which make up the atmosphere, 
are found in every part of the earth, both on the highest moun¬ 
tains and in the deepest mines. Besides pure air, which is 
composed of oxygen and nitrogen, in every part of the atmos¬ 
phere two other gases, carbonic acid and ammonia, with watery 
vapor, are found as leading constituents. 

106. The atmosphere surrounds our globe to the height of 
abo<ut forty miles, and far beyond this height it has been 
proved to exist in a state of extreme rarity. It is the breath 
of life to animals, for no other gas, or combination of gases, is 
adapted to this purpose ; it is equally necessary to plants which 
absorb it, and the gases of which it is the vehicle. By respi¬ 
ration, it acts upon the blood of animals, renewing perpetually 
its vital properties, and through the leaves of plants it perfects 
the sap and renders it suitable for their nourishment. No 
animal, however low in the system of creation, has been found 
without the means of introducing air freely into every part 
of its system. 


WATER. 


107. Water, when analyzed, has been found to consist of 
two volumes of hydrogen to one of oxygen, and eight of oxygen 
to one of hydrogen, by weight. The method of analysis by 
galvanism has been described (80). The following is another 
method : 


A gun-barrel (Fig. 37,) is 
made to pass through a fur¬ 
nace. It is connected at one 
end with a retort holding 
some water. When the gun- 
barrel has become red hot in 
the furnace, heat is applied 


Pig. 37. 



beneath the retort by a lamp, and the vapor comes through the 
gun-barrel, where it is decomposed by the ignited surface. 
The oxygen unites with the red-hot iron, and the hydrogen, 
issues from the end of the gun-barrel. 


Explain Fig. 36. What is meant by the diffusion of gases ? What is the 
effect of this principle upon the gases of the atmosphere 1 

10G. How far above the earth does the atmosphere extend ? What is said 
of its importance to animals and plants 1 

107. What is the composition of water 1 Explain Fig. 37. What may be 
used instead of the gun-barrel in this experiment ? In this case how will the 











THE ELEMENTS AND THEIR COMBINATIONS. 71 

A porcelain tube may be used instead of the gun-barrel, 
if it is loosely filled with iron turnings, which when red hot, 
absorb the oxygen, and their increase in weight will show the 
amount of oxygen absorbed. If the experiment be accurately 
performed, it will be found that eight times as much oxygen, 
by weight, has been obtained, as hydrogen. ( 20 ) 

108. At a very high temperature , water is decomposed, as 
is seen when a small portion of water is thrown on an in¬ 
tensely hot fire. Water thrown on a large quantity of burn¬ 
ing tar increases its combustion, and the same effect is pro¬ 
duced in large fires, where water thrown from engines increases 
the rapidity and energy of the fire. If a ball of platinum of 
the size of a large pea, with a wire attached to it, be heated 
to bright whiteness till it begins to show signs of fusion, and 
then plunged into hot water, minute bubbles of gas rise with 
the steam, which consist of a mixture of oxygen and hydro¬ 
gen. 

109. The synthesis (4) of 
water may also be performed 
in the following manner. Put 
into one of the retorts in Fig. 

38, some chlorate of potash, 
and apply heat beneath ; in¬ 
to the other put the ingre¬ 
dients for making hydrogen 
gas (11.0). Tie some plati¬ 
num sponge to a wire of the 
same metal, several times 
coiled around it; heat this red hot, and immerse it in the 
mixed gases in the jar, a, so that the hydrogen shall blow upon 
one side, and the oxygen upon the other side ; an explosion 
will ensue, after which the gases will burn more quietly. The 
platinum sponge will glow with the intensity of the heat, and, 
by the union of the gases, water will be formed, and will be 
deposited on the inner surface of the jar a. ( 21 ) 

• The same effect may be produced by burning a jet of hydro¬ 
gen gas in a tall glass tube. Water will be formed on the in¬ 
side of the tube, by the union of hydrogen and the oxygen of 
the air. Water is therefore composed of oxygen and hydrogen, 
as is determined by both analysis and synthesis. 


Fig. 38. 



amount of oxygen absorbed be determined ? How much more oxygen than 
hydrogen, by weight, does water contain ? 

108. What facts show that water is decomposed at a very high temperature ? 

109. Explain Fig. 38. In what other way may the synthesis of water be 
performed ? 














72 


ELEMENTS OF CHEMISTRY. 


HYDROGEN. 


Fig. 39. 


110. Hydrogen is never found in a free state. For the pur¬ 
poses of experiment it is always obtained by deoxidizing water. 
Thus, in passing the vapor of water through a red-hot iron 
tube, the red-hot surface absorbs the 
oxygen, and the hydrogen issues from 
the end of the tube. A more common 
method of obtaining hydrogen is repre¬ 
sented in Fig. 39. The flask,/, is pro¬ 
vided with a bent tube, c, which de¬ 
scends through the cork into the flask. 
The cork is first taken out, and a few 
small pieces of zinc are placed in the 
flask. Upon these, diluted sulphuric 
acid is poured. The flask is now closed with the cork, and 
the gas comes over at the end of the bent tube. ( 22 ) 

The flask contains 

Water l -^y^ ro & en . Hydrogen. 

\ Oxygen [escape, a. gas.] 

Zinc-oxide of zinc. 

[unites •with sulph. acid.] 

sulph. acid_—^.sulphate of zinc, soluble salt. 

[remains in solution.] 



From the diagram it is evident that the direct action in 
forming hydrogen is between the water and the zinc, the latter 
drawing away the oxygen from the water, and leaving the 
hydrogen free. But without the presence of sulphuric, or some 
other acid, the zinc almost instantly becomes coated with the 
oxide of zinc, and this coating, being insoluble in water, pre¬ 
vents all further action until the acid is added, which dissolves 
it, and thus leaves a bright surface of zinc to the renewed ac¬ 
tion of the water. 

But besides this agency of sulphuric acid, its presence also 
facilitates the process by disposing affinity (p. 60), for if acid 
be not present, a piece of zinc, however bright, or even when 
heated, will not become oxidized, or, in other words, will not 
produce the decomposition of water by withdrawing its oxygen, 
until after a long time, and but to a very small extent. That 
the hydrogen is not derived from the sulphuric acid, may be 


110. Is hydrogen ever found in a free state ? How is it always obtained for 
the purpose of experiment? Explain Fig. 39. In forming hydrogen by this 
method, between what two substances is the direct action ? How does zinc 
form hydrogen from water ? Why is the presence of some acid necessary ? 
What is meant by disposing affinity ? Does sulphuric acid facilitate the forma- 







THE ELEMENTS AND THEIR COMBINATIONS. 


73 


proved experimentally, by adding concentrated acid to zinc, 
when no action will take place, but this will commence when 
water is added. A large quantity of water will be required 
to produce the greatest action. ( 23 ) 

111. Hydrogen is a colorless gas; as ordinarily obtained it 
has a smell slightly fetid, but when passed through lime water, 
and afterwards through alcohol, it becomes pure, and then has 
no smell. Like nitrogen, it is hostile to life, but is not poison¬ 
ous, and takes away life by suffocation. 

It is the lightest of all known forms of matter. When in¬ 
haled, as it may be without injury if pure,* it gives to the 
voice a peculiar shrillness. ( 24 ) It produces, after two inhala¬ 
tions, disagreeable sensations, with a loss of muscular power. 
It combines with a large number of substances, and many of 
its compounds are of great importance. It is sometimes em¬ 
ployed in inflating balloons. Soap-bubbles, inflated with hy¬ 
drogen gas, ascend like balloons. To inflate the soap-bubbles, 
a bladder, furnished with a pipe and stop-cock, is employed. 
The pipe being dipped in a solution of soap, a gentle pressure 
is given to the bladder, when the bubbles will be formed, and 
finally rise from the pipe rapidly to the ceiling. ( 25 ) Musical 
tones are produced when a small jet of this gas is burned in a 
glass or other tube. These 
tones are also produced by 
several other gases. They 
are probably caused by a 
series of explosions, which 
succeed each other rapidly, 
as the flame nearly goes 
out, and relights in the tube. 

( 26 ) Though highly inflam¬ 
mable, hydrogen is not a 
supporter of combustion. 

Its inflammability, and, at 
the same time, the fact 
that it extinguishes the com¬ 
bustion of bodies introduced 
within it, may be shown by 
the following arrangement. A bottle, a , (Fig. 40,) is provided 

* It is generally sufficiently pure for this purpose, but it should not be inhaled 
too long, as death has resulted from a want of caution in this respect. 


Fig. 40. 



tion of hydrogen by increasing the affinity of the zinc for the oxygen of the 
water? By what experiment may it be proved that the hydrogen is not de¬ 
rived directly from the acid ? _ , 

111. Mention some of the properties of hydrogen. What effect does it pro- 

4 























74 


ELEMENTS OF CHEMISTRY. 


c a 


Pig. 41. 
96 


“0 


with an india-rubber tube, which conveys the gas to a bell- 
glass, b. This bell-glass is held in the hand, and the hydro¬ 
gen allowed to drive out the air, which it does by its greater 
lightness filling the bell-glass gradually, from top to bottom. 
The hydrogen is now set on fire by a candle at a bottom of the 
jar, which goes out itself as it enters the gas within the bell- 
glass, but is relighted at the mouth as it is drawn out 
again. ( 27 ) 

112. Hydrogen explodes when mingled with the common 
air, and more violently when mixed with oxygen gas. The 
mixture may be made in a strong brass cylinder, or pistol a, 

(Fig. 41.) A cork is inserted at c, and the 
finger held over the small orifice b. On re¬ 
moving the finger, and instantly applying 
a match, the mixed gases explode and drive 
out the cork. The gases are mixed in the 
proportions of two volumes of hydrogen to 
one of oxygen, or in those proportions in which they unite to 
form water. 

113. The most intense heat, except, perhaps, that pro¬ 
duced by galvanism, is made by burning hydrogen with oxygen, 
By this method the Drummond-light, and the flame of the 
compound blowpipe* are produced. The latter causes the 
most intense heat which the chemist can command, and in a 
space not greater than that occupied by the flame of a 
candle. 

114. Water is a chemical combination ; air is a mecha.ni- 
cal mixture. In air, therefore, the peculiar properties of each 
component, oxygen and nitrogen, are to a certain extent pre¬ 
served. But in water, the peculiar properties of both oxygen 
and hydrogen are entirely lost. Oxygen is the greatest of all 
supporters of combustion, and hydrogen the most inflammable 
body; but water is used for extinguishing fire, and, therefore, 
is neither inflammable nor a supporter of combustion. Oxygen 

t 

* These will be described hereafter. 


duce on the voice when inhaled ? What is said of its power of combination, 
and the importance of its compounds ? For what is it sometimes employed ? 
In what manner may soap-bubbles be inflated with hydrogen ? How are mu¬ 
sical tones obtained from a jet of hydrogen 1 Explain Fig. 40- 

112. Explain Fig. 41. 

113. For what purpose is the mixture of oxygen and hydrogen gases em¬ 
ployed ? 

114. What is said of the nature of the combination of the elements of water 
as compared with those of air ? In what respects do the properties of water 
differ from those of its components ? Why does air possess many of the prop¬ 
erties of its components ?—Ans. Because it is a mechanical mixture, and not a 
chemical combination ? 






THE ELEMENTS AND THEIR COMBINATIONS. 75 

is exciting and stimulating to the vital processes ; watery va¬ 
por, if inhaled, would produce death by suffocation. 

115. Some of the leading properties of water are the follow¬ 
ing : When pure, it is a transparent, colorless liquid, which 
has neither taste nor smell. It boils at 212°, although the 
temperature of the boiling point, depends on the degree of 
pressure upon its surface. Under a vast pressure, it has been 
found to undergo a slight diminution of volume, amounting to 
j oioo part, for a pressure equal to that of the atmosphere, or 
15 pounds to the square inch. It cannot he found pure in na¬ 
ture, but the purest water is obtained by melting freshly fallen 
snow, or by receiving rain in open vessels, at a distance from 
houses. Even this water is not absolutely pure, for, if placed 
under the exhausted receiver of an air-pump, bubbles of gas 
escape from it, and this gas is found to contain much more 
oxygen than common air. It also contains more or less of 
ammonia, which it absorbs from the atmosphere. All common 
water sinking through the earth, and running beneath the 
surface, becomes charged with earthy and saline matters ; 
hence, to obtain pure water, it is necessary for the chemist to 
distil this water. The solvent 'powers of pure water are, in 
some cases, greater than those of common water. 

The chemical properties of water are of the greatest impor¬ 
tance. Its solvent powers far exceed those of any other body. 
It absorbs gaseous bodies, and holds in solution solid sub¬ 
stances, acids ( 28 ), alkalies, and salts, while it does not alter 
their properties, or is neutral to all these bodies. These sol¬ 
vent powers are, generally, increased by heat; but in a few 
cases, as in the case of common salt, cold water holds as 
much in solution as warm water, and in a few instances also, 
its solvent powers are greater than those of warm water. ( 29 ) 

116. The purposes which water serves are numberless, and 
of vast importance. All the tribes of the vegetable, as well 
as those of the animal kingdom, are nourished by water. 
Though perfectly inodorous in itself, watery vapor is the me¬ 
dium of the sweetest perfumes, and there is no bloom or beauty 
in nature, without the presence of water. Even the sky has 
a deeper blue when the atmosphere is fully charged with 


115. Mention some of the leading properties of water. What is the effect 
of a vast pressure upon water ? Is water found pure in nature 1 How is the 
purest water obtained ? Is water thus obtained absolutely pure ? What is said 
of common water ? How do the solvent powers of pure water compare with 
those of common water ? What is said of the chemical properties of water 1 
What is the effect of an increase of temperature on its solvent powers ! 

116. «What are some of the purposes served by water ? What effect has the 
presence of moisture upon the color of the sky, and upon the light of the sun 





76 


ELEMENTS OF CHEMISTRY. 


moisture, and sunlight and starlight are much more intense 
before and after a shower of rain. In southern latitudes, 
where a warmer climate produces a greater amount of watery 
vapor, the beauty of the sky by night, aud the brilliancy with 
which the sun shines by day, are unknown in more northern 
countries. 

The health of large and populous cities is dependent on an 
abundant supply of water ; as a detergent, as an absorbent 
of the most deleterious gases, as a powerful mechanical agent 
in the waterfall and in the form of steam, water is applied to 
a great variety of purposes. It is the most indispensable bev¬ 
erage to man, and to all animals that inhabit the earth ; it is 
a solvent of a great variety of bodies, and a constituent part 
of many; it is a medium of chemical action, and its presence 
is necessary in a great variety of cases. The crystallization 
of bodies rarely takes place without the presence of water, so 
that this is the source of the beauty of inorganic nature, as 
well as that of the organized world. ( 30 ) Its own crystals, in 
the form of snow, are greater in variety, and more beautiful 
in form, than those of any other substance. Neither earth 
nor air is so populous with life as water, from the animals that 
swarm in the pool or spring, to those that fill the waters of 
the ocean. 

We cannot, therefore, too much admire a substance so beau¬ 
tiful in itself, so bountifully provided, and so wonderfully 
adapted to the wants of man. “ Wherever a spring rises or a 
river flows, there should we build altars and offer sacrifices.”* 


CARBON. 

117. This is the last of the organogens, or those elements 
which chiefly prevail throughout the animal and vegetable 
kingdoms. Carbon is also largely diffused in the mineral 
kingdom. Its most striking peculiarity is the different condi¬ 
tions under which it occurs. Among these are : 

* Seneca. 


and the stars ? What is said of the appearance of the sky in southern lati¬ 
tudes 1 What other purposes are served by water 1 What relation has water 
to the crystallization of bodies 1 How do the crystals of snow compare with 
those of other substances ? How does water compare with the earth or the 
atmosphere, as a medium of life ? 

117. What are some of the sources of carbon ? What are some of the forms 
under which it is found ? What is said of the diamond ? What are some of 
the crystalline forms under which the diamond is found ? What other proper¬ 
ties of the diamond are mentioned ? Mention some of the properties of plum¬ 
bago. Is there any connection between the crystals of plumbago and the crys- 



THE ELEMENTS AND THEIR COMBINATIONS. 


77 


(1.) The diamond, which is nearly pure carbon. It was 
probably fused at a high temperature, and crystallized by 
slow cooling, from this state of fusion. The figures beneath 


Fig. 42. 


Fig. 43. 


Fig. 44. 


Fig. 45. 



represent some of the forms of the diamond. Of these, Fig. 
42. is a cube, Fig. 43. a regular octahedron, Fig 44. a rhom¬ 
bic dodeca-hedron , and Fig. 45. an octahedron with its faces 
rounded, or curved ; diamonds occur of this form, sometimes 
almost spherical. The diamond is nearly infusible, but when 
exposed to the flame of a condensed mixture of gases, or the 
heat produced by a powerful galvanic battery, it is fused. If 
heated without contact of air, it is not altered, even by a very 
intense heat, but when heated to ordinary redness in a vessel 
of oxygen, it burns with facility, yielding carbonic acid gas. 
It is the hardest substance known. It is cleaved or split 
without difficulty, in particular directions, but can only be cut 
or abraded by the fragments or powder of the diamond itself. 
A very useful application of the diamond is made by the gla¬ 
zier, in cutting glass. A diamond having the rounded octa¬ 
hedral figure, held with its edge on the surface of glass, and 
drawn along with a gentle pressure, causes a split or cut which 
penetrates to a considerable depth into the glass, and deter¬ 
mines its fracture with perfect certainty.( 31 ) 

(2.) Carbon also occurs in the various forms of charcoal, 
anthracite coal, coke, &c. 

(3.) Plumbago. This substance has the metallic lustre, is 
opaque, and so soft and unctuous that it is used to diminish the 
friction of machinery. Crystals of plumbago or graphite are 
not common, but when they occur they have the figure of a* 
short six-sided prism,—a form which has no geometrical rela¬ 
tion to that of the diamond. This mineral is used in lead pen¬ 
cils ; it is somewhat rare. The finest and most valuable is 
brought from Borrowdale, in the north-western part of England. 
It is found there in an irregular vein, traversing the slate beds. 


talline forms of the diamond? Whence is the finest plumbago obtained? 
Mention some of the properties of lampblack. What is meant by the allo¬ 
tropism of bodies ? What is the purest form of carbon ? What does plumbago 
usually contain ? 








78 


ELEMENTS OF CHEMISTRY. 


(4.) Lampblack is a powerful absorbent of light and heat, 
and possesses a very strong affinity for oxygen, sometimes 
taking fire spontaneously in the air. 

These substances, although so entirely different from each 
other, are all composed of nearly pure carbon. They form ex¬ 
amples of the allotropism of bodies (99.) Substances could 
hardly be found differing from each other more than the dia¬ 
mond and charcoal, or lampblack, plumbago, &c. ; yet these 
substances are all carbon, very nearly pure. In the diamond, 
carbon is transparent and a non-conduc’tor of electricity ; but 
in plumbago and charcoal it is opaque, possessed of. metallic 
lustre, and a good conductor of electricity ; and in these forms, 
therefore, it differs not only from the diamond, but from the 
other non-metallic elements, which, like the diamond, are non¬ 
conductors of electricity, and generally transparent. The 
diamond is the purest form of carbon; charcoal the next, 
plumbago generally contains a little iron, although this is 
sometimes no more than a trace. Lampblack is very nearly 
pure carbon. 

118. Charcoal may be formed, for the purposes of experi¬ 
ment, by plunging small pieces of wood beneath melted lead 
or tin, or beneath sand heated to redness in a crucible. By 
this process the volatile parts of the wood will be driven off, 
and the carbon or charcoal remain behind. ( 32 ) 

In preparing charcoal on a large scale, piles of wood are 
erected, which are covered with turf and moistened earth, and 
the wood is then kindled. This would be extinguished, how¬ 
ever, for want of air, if holes were not made iu different parts 
of the kiln, through which fresh air is admitted, and the burnt 
air escapes. Only so much should be admitted as is necessary 
for expelling the volatile parts of the wood. When this has 
been accomplished near the holes, they must be closed, and 
new ones made at other points. At last all the openings are 
carefully stopped, that the fire may be put out. When cold, 
*the wood will be found thoroughly charred, the shape of the 
knots and the rings being still perceptible. All the vessels of 
the wood are so perfectly preserved, that when a section of the 
charcoal is magnified many hundred times by the solar micros¬ 
cope, the structure of the wood from which it is formed is still 
visible. One pound of wood yields about one fifth of a pound 
of charcoal. 


118 . How may charcoal be formed for the purposes of experiment? De¬ 
scribe the process of preparing charcoal on a large scale. Ho\y much charcoal 
can be made from a pound of wood ? How is charcoal prepared for the manu¬ 
facture of gunpowder ? What kinds of wood are selected for this purpose ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


79 


Charcoal for the manufacture of gunpowder, is prepared in 
cast-iron cylinders. The cylinders are placed across a furnace, 
and there is a small vent left for the escape of the volatile 
parts of the wood, but not sufficient for free access of air. 
Alder, dogwood, and willow, are the kinds of wood preferred 
in making charcoal for gunpowder. 

119. Charcoal is unchanged by heat, when not exposed to the 
air. After intense ignition, it becomes hard enough to scratch 
glass and wear a file, and particles of coke have been obtained 
so hard as to cut glass like a diamond. After being ignited, 
it absorbs the gases without alteration, and heat is developed 
during the process. When first made it is very apt to take fire 
when thrown into heaps, by the absorption of oxygen from the 
atmosphere. The snapping of coal when placed in the fire, is 
owing to the sudden expansion of the gases and vapors con¬ 
fined within its pores. If a piece of recently ignited charcoal 
be placed under a jar which stands over mercury, it will absorb 
many times its volume of air, as will be shown by the rise of 
the mercury within the jar. 

120. Charcoal is unaltered by air or moisture. The figures 
on the dial plates of steeples, which are painted black, often 
stand out in bold relief, while the rest of the wood, painted 
white, is worn away. This preserving power of black paint 
is owing to the fact that charcoal forms its basis. The beams 
of the theatre at Herculaneum were converted into charcoal by 
the lava which overflowed that city, and for seventeen hun¬ 
dred years they have remained entire, and still present the ap¬ 
pearance of recently formed charcoal.( 33 ) 

121. Charcoal has the power of absorbing the bad odors and 
coloring principles of most animal and vegetable substances. 
Tainted meat is made sweet by burying it in powdered char¬ 
coal and foul water is purified by being strained through 
it.( 34 ) The sirup of the sugar-cane is rendered colorless by 
being passed through sacks of animal charcoal (bone-black), 
prepared by igniting bones.( 35 ) After being used for some time, 
this charcoal loses its decolorizing power, but regains it on 
being heated to redness. 

Charcoal is of great service in reducing metals from their 


119. Mention some of the properties of charcoal. To what is the snapping 
of coal when placed on the fire owing ? How may the power of recently igni¬ 
ted charcoal to absorb air be shown by experiment ? 

120. What are the relations of charcoal to air and moisture ? Mention some 
examples. 

121. What is said of the absorbent properties of charcoal ? How is charcoal 
that has lost its decolorizing power restored ? In what way does charcoal re¬ 
duce metals from their oxides ? 



80 


ELEMENTS OF CHEMISTRY. 


oxides. This it does by its great affinity for oxygen, which 
causes it to take the oxygen from the oxide and reduce the 
metal.( 3C ) 


SYMBOLS. 


122. The composition of bodies is most conveniently ex¬ 
pressed by symbols of the elements of which they are com¬ 
posed. For this purpose, every elementary substance is desig¬ 
nated by the first letter of the Latin name in capitals ; or, 
where several names begin alike, by this and the most char¬ 
acteristic small letter in the word The following table con¬ 
tains the symbols and combining numbers of the organogens. 
The meaning of the term, combining number , is somewhat 
complex, and requires full illustration to be understood. It 
will, therefore, be explained more fully hereafter, when many 
of the combinations of the gases being known, they may be 
employed in illustration. 



Symbol. 

Combining Number . 

Oxygen, 

0 . 

8. 

Nitrogen, 

N. 

14. 

Hydrogen, 

H. 

1 . 

Carbon, 

C. 

6. 


SULPHUR. 

123. Sulphur is exhaled in large quantities from volcanoes, 
either in a pure state, or in combination with hydrogen ; by 
condensing in fissures, it forms sulphur veins, from which the 
greater part of the sulphur of commerce is derived. It exists 
also in combination with many metals( 37 ), as iron, lead, copper, 
zinc, &c.«, in rocks and mineral waters.( 38 ) Some plants also 
contain sulphur, and it is found in all animal substances. It 
is a pale, greenish-yellow solid, without smell, unless when 
warm or rubbed, when it gives off a smell unlike that of any 
other body, and therefore called the smell of sulphur. It is 
very friable, a roll of it emits a crackling sound, and sometimes 
breaks when held in the warm hand. It melts readily at a 
heat only a few degrees above that of boiling water, forming 
a transparent and nearly colorless liquid. In melting the 


122. In what manner is the composition of bodies most conveniently ex¬ 
pressed ? Whence are these symbols obtained ? Write the symbols and the 
combining numbers of the organogens. 

123. What is the chief source of sulphur ? In what other forms does it also 
exist ? What are some of its properties ? At what temperature does it melt ? 
What does it form in melting ? What is the effect of an elevation of tempera¬ 
ture upon this liquid ? At what temperature does sulphur sublime ? What 



THE ELEMENTS AND THEIR COMBINATIONS. 


81 


solid portion sinks, showing that it is heavier than the liquid. 
Sulphur, therefore, contracts in congealing, while ice expands. 
It is readily crystallized, as it does not pass through the pasty 
state (like wax) in congealing. As the temperature is elevated, 
the liquid becomes orange-yellow and thick, and at 482° passes 
abruptly into a dark brown. At about 600° it sublimes, and 
the condensed product is called the flowers of sulphur .( 39 ) If 
heated for a time at this temperature, and then suddenly 
poured into cold water at a low temperature, it becomes, on 
cooling, elastic like india-rubber, and may be drawn out into 
long threads. By keeping for a few days, it slowly returns to 
its usual condition. 

124. Sulphur crystallizes in a very beautiful manner. When 
the temperature descends to about 231° the particles of sulphur 
in solidifying form needle-shaped crystals, which start from a 
point on the side, and shoot across the fluid mass. On these 
new crystals are formed, and this process is continued until the 
whole mass is solidified. Fig. 46. is a section of a crucible, 
showing the form of this crystallization. A 
large crucible is filled with sulphur, placed 
in a furnace, and the sulphur allowed to 
melt very gradually. When all the sulphur 
is melted, it is removed from the furnace 
and placed on moist sand. The top is also 
covered up, that the sulphur beneath may 
cool as fast as that on the surface. After 
a solid crust is formed on the surface, this is 
pierced in two places on opposite sides, and 
the melted sulphur poured out through one of the openings 
thus made. That which remains will be found beautifully 
crystalline. The native crystals obtained from Italy are some¬ 
times two or three inches in diameter. Some of their forms 
are represented in the accompanying figures. 

Fig. 49. Fig. 50. 

4 



Fig. 47. Fig. 48. 



Fig. 46. 



is the condensed product called 1 If suddenly thrown into cold water at this 
temperature, what effect is produced ? Is the elastic substance thus formed 
permanent ? 

124. Explain Fig. 46. 


4’ 








82 


ELEMENTS OF CHEMISTRY. 


125. The range of combination of sulphur is very wide, and 
its compounds are very important. Sulphurets* are com¬ 
pounds of sulphur with electro-positive or inflammable bodies. 
Sulphates are salts containing sulphuric acid ; sulphites , salts 
containing sulphurous acid. Sulphur is of great importance 
in the arts. It is one of the ingredients of gunpowder, and 
forms the basis of all kinds of matches. The most important 
of the acids, sulphuric acid, is made from sulphur. Sulphur 
is also a valuable agent in medicine. 


SELENIUM. 

126. Selenium resembles sulphur in many of its properties. 
It is brittle, and so soft as to be easily scratched. It softens 
when heated, becomes semi-fluid at 212°, and perfectly fluid at 
a somewhat higher temperature. In cooling it remains soft 
for a long time, and may be worked like sealing-wax and 
drawn out into long, elastic, transparent threads. Its affinity 
for oxygen is less than that of sulphur. When gently heated 
in the air it sublimes without change, and does not take fire 
until more strongly heated, as by contact with flame. It then 
burns in the air with a reddish blue flame, and in oxygen gas 
with a flame which is white below and bluish-green above. 

Selenium is one of the least abundant of the elements, but 
is found in minute quantity in several ores of copper, silver, 
lead, bismuth, tellurium, and gold, in Sweden and Norway. 
It has also been found in the Lipari islands, associated with 
sulphur, and is contained in the red matter deposited from 
some kinds of sulphuric acid, especially after the acid has been 
diluted with water. 

PHOSPHORUS. 

127. The most remarkable quality of phosphorus is its great 
inflammability. ( 40 ) From its property of emitting light in the 
dark, it derives its name, which signifies “ lighlrbearer.” The 

* These salts are now very generally called sulphides. 


125. What is said of the range of combination of sulphur and the importance 
of its compounds? What is meant by the term sulphuret ?—the term sul¬ 
phate ?—the term sulphite ? What are some of the uses of sulphur ? 

126. What body does selenium greatly resemble? Mention some of its 
properties. How does its affinity for oxygen compare with that of sulphur ? 
What is the action of heat upon selenium ? Is selenium an abundant or a rare 
substance ? Where has it been found ? 

127. What is the most remarkable property of phosphorus ? Whence does 



THE ELEMENTS AND THEIR COMBINATIONS. 


83 


term phosphorescence, which applies to a large class of bodies, 
has a similar origin. ( 41 ) 

Phosphorus is almost colorless, transparent after slow cool¬ 
ing, and semi-opaque after rapid cooling. If suddenly dropped 
into very cold water or on a surface of ice it will instantly 
turn black. It may be cut with a knife,* and the fresh surface 
has a waxy lustre. It fuses at 113°, and in the fused state 
presents the appearance of a transparent oil. After fusion it 
cools, if at rest, down to 97° before it solidifies, and when 
solidification takes place its temperature rises again to 113°. 
It boils at 550°, and is converted into a colorless vapor. When, 
rubbed or heated to about the temperature of 110°, it takes 
fire and burns with great rapidity, emitting an abundance of 
acid fumes.( 42 ) In oxygen its combustion is so intensely 
brilliant that the eye can hardly bear the light.( 43 ) 

Under the influence of solar light phosphorus is transformed 
into a remarkable isomeric compound of a red color, possessing 
entirely different properties from those of ordinary phosphorus. 
While the latter melts at 48°, red phosphorus can be heated 
to 482° without fusion. At 500° it returns to the state of or¬ 
dinary phosphorus. Red phosphorus has no perceptible odor 
at common temperatures. It undergoes no alteration by expo¬ 
sure to air, and does not become luminous until it has been 
heated as high as 392°. It does not combine with sulphur, 
even when the latter is fused, while ordinary phosphorus, 
heated slightly with sulphur, combines with it with explosion. 

Phosphorus has a variety of uses, but the most important 
purpose which it serves is in the structure of the human frame, 
and in that of all land animals. Phosphorus, in the form of 
phosphate of lime, is found wherever strength and rigidity in 
the animal frame are required. The internal bony portions 
of the ear, where the greatest solidity is required, are the den¬ 
sest parts of the skeleton, and phosphate of lime enters most 
largely into the composition of these bones. The enamel 
of the teeth consists almost wholly of phosphate of lime. 
The skeleton of a man is considered as weighing from 10 to 
12 lbs., and therefore contains from l-j to 2 lbs. of phosphorus. 
Phosphorus is employed in the arts for the manufacture of 
matches, and for this purpose 200,000 lbs. are used annually 
in the city of London alone. 

* This should be done under water. 


it derive its name, and what does this signify ? What are some of its proper¬ 
ties ? At what temperature does it take fire when rubbed or heated . Wha.t 
are some of the properties of red phosphorus ? What are some of the uses of 
phosphorus ? Write the symbols and combining numbers of the pyrogens, 





84 


ELEMENTS OF CHEMISTRY. 


The following table contains 
numbers of the pyrogens : 

the 

symbols and combining 

Sulphur, 

S. 

16. 

Selenium, 

Se. 

40. 

Phosphorus, 

P. 

31. 

CHLORINE. 



128. The great natural source of chlorine is common salt 
(chloride of sodium), of which it composes about 60 per cent. 
Into a retort are put 3 parts of salt and 1 of oxide of man¬ 
ganese. The mixture is well shaken, and 2 parts of sulphuric 
acid, previously diluted with 2 of water, added. Chlorine is 
evolved, and the extrication may be quickened by the applica¬ 
tion of a gentle heat. 

In the retort were put 


Chloride of 5 chlorine 
Sodium, ^ sodium 
Sulphuric acid, 

Peroxide of < oxygen 
Manganese, ( protoxide of manganese - 
Sulphuric acid.-— 


■Chlorine. 

[passes off in gus.j 

’sulphate of soda, soluble salt. 

[remains in solution.] 

-sulph.of manganese, soluble salt 

[remains in solution.] 


129. This method of obtaining chlorine is largely used in 
the arts in preparing this gas for bleaching linen and cotton 
goods, and rags for the manufacture of paper. On a small 
scale , the following method will be found more convenient. 
Provide a flask with a tube bent twice at right angles, and 
passing through a cork which fits tightly in the flask. From 
the flask the tube passes into a bottle, and should be of sufficient 
length to reach nearly to the bottom of the bottle. Into the 
flask put 1 part of black oxide of manganese, and pour upon it 
2 parts of hydrochloric acid. The chlorine will issue abun¬ 
dantly, and may be received in the bottle by the displacement 
of air. Towards the latter part, the process may be hastened 
by the application of heat. 


tt:. ii • Cchlorine . Chlorine. 

Hydrochloric) _ [pa8se8 off in gas-] 


acid, 

Peroxide of 
Manganese, 


Hydrochloric ( chlorine 


< , , i passes on 

) hydrogen- water. 

— — [remains in the solution. 

C oxygen 

< manganese -——^=»chloride of manganese, soluble salt. 

( Oxygen *■_[remains in the solution.] 


acid. 


( hydrogen- —water. 

[remains in the solution.] 


128. What is the great source of chlorine ? Explain the method of preparing 
chlorine from common salt. 

129. Explain the common process of obtaining chlorine for experiment. 










the elements and their combinations. 


85 


130. Chlorine is a yellowish green gas. ( 44 ) It has an as¬ 
tringent taste and a disagreeable odor. ( 45 ) It is one of the 
most suffocating gases, exciting spasms and great irritation in 
the throat and lungs, and should not be incautiously breathed, 
even when considerably diluted with air. Some relief from 
the sensations produced by it, may be obtained by inhaling the 
vapor of ether or alcohol. If a mouse, or other small animal, 
be dropped into a jar of chlorine, it will instantly fall dead. 
Mingled with hydrogen, it becomes explosive, and may be in¬ 
flamed by the direct rays of the sun. ( 46 ) It is about two and 
one half times heavier than air. ( 47 ) Under the pressure of 
about four atmospheres, it is a limpid fluid of a bright yellow 
color. Cold water, recently boiled, absorbs twice its volume 
of chlorine, and yields it again when heated. 

131. Chlorine unites w r ith some substances with the evolu¬ 
tion of light and heat, and hence is called a supporter of 
combustion. On plunging a lighted candle into chlorine, it 
burns for a short time with a small red flame, and emits a 
large quantity of black smoke,—the carbon of the candle which 
does not burn in chlorine. It may be relighted, if the wick is 
large and red hot when introduced into the gas. Phosphorus 
takes fire in it spontaneously, and bums with a pale white light. 
Melted sulphur also takes fire in chlorine, and burns rapidly. 
Several of the metals, such as tin, copper, arsenic, antimony, 
and zinc, when introduced into chlorine, in a state of powder 
or of fine leaves, are suddenly inflamed. ( 48 ) Chlorine is indi¬ 
rectly one of the most powerful oxidizing substances which we 
possess. It oxidizes by withdrawing the hydrogen, for which 
it has a great affinity from the water in which different sub¬ 
stances are dissolved, and thus the oxygen of the water being 
set free, unites with the substances in solution. This process 
always oxidizes bodies that have a strong affinity for oxy¬ 
gen. ( 49 ) 

132. Chlorine bleaches and destroys all the colors derived 
from the animal or vegetable kingdoms. In consequence of 
this property, chlorine has become a most important agent in 


130. What are some of the properties of chlorine? What is its effect on a 
mouse or other small animal? How may a mixture of chlorine and hydrogen 
be inflamed ? What is the specific gravity of chlorine ? Under what pressure 
does it become fluid ? To what extent is it absorbed by cold water ? What 
is the effect of heat on chlorine water ? 

131. Why is chlorine called a supporter of combustion? What effect has 
this gas upon a lighted taper?—on phosphorus? What other examples are 
mentioned of bodies that take fire spontaneously in chlorine ? In what way 
does chlorine effect the oxidation of bodies ? 

132. What is said of the bleaching properties of chlorine ? What salt of 
chlorine is employed in the process of bleaching ? 



86 


ELEMENTS OF CHEMISTRY. 


bleaching. Linen, cotton, paper, and other materials, may 
now be rendered perfectly white by it in a few hours, while, 
by the old method of laying them on the grass in the sun, 
weeks, and even months, were required to produce this effect. 
Chlorine is not, however, used directly, as it would be injurious 
to the health of the laborers, but chloride of lime is employed, 
a salt from which the chlorine is separated by mere exposure 
to the air. ( 60 ) 

133. Chlorine is one of the best and most powerful sub¬ 
stances that can be used for the purpose of disinfection ; but 
its use for this purpose requires care. Bleaching powder, 
mixed with water, and exposed to the air in shallow vessels, 
becomes slowly decomposed by the carbonic acid of the at¬ 
mosphere, and the chlorine is evolved. If a more rapid dis¬ 
engagement of chlorine be wished, a little acid of any kind 
may be added, but an excess of chlorine is as bad as the gases 
it is designed to remove. It disinfects the air by decomposing 
the noxious gases, uniting with one of the constituents, and 
precipitating the other in the solid or harmless form. Several 
of the gases to be described hereafter, as sulphuretted hydrogen, 
are decomposed in this way. 


IODINE. 

134. Iodine is an element found principally in the ashes of 
sea-weed and of sponge. It also exists in all aquatic plants 
and animals, but has not yet been detected in terrestrial 
plants. The proportion of iodine in plants depends more upon 
their situation than their nature. The same plants which 
contain iodine when growing in water, do not contain it if devel¬ 
oped out of water ; those in running streams or in large masses 
of water subject to agitation by the winds, contain more than 
those in ponds, marshes, and stagnant water. Iodine is found 
not only in plants growing in large rivers, but in those of 
every rivulet, pond and marsh. It also exists in coal in con¬ 
siderable quantity, and some of the iodine remains even in the 
coke, after the more volatile gases have been driven off by heat. 
Iodine is abundant in many minerals, and is also contained in 
fermented liquors, in milk, &c. Iodine is, therefore, widely 


133. Wliat is said of chlorine as a disinfectant ? In what manner does chlo¬ 
rine disinfect the air ? 

134. Where is iodine found ? What element does it resemble in its general 
character ? What are some of its properties ? What is the specific gravity 
of its vapor ? Why is iodine regarded as a supporter of combustion 1 




THE ELEMENTS AND THEIR COMBINATIONS. 


87 


diffused over the earth, and usually accompanies salt and 
other chlorides. By the evaporation of the waters of the globe 
it rises, and becomes diffused through the atmosphere. Through 
this medium it is inhaled, and four fifths of the iodine con¬ 
tained in the air which is breathed becomes fixed in the body. 
It descends in rain and also in snow, although the latter, un¬ 
der the same circumstances, is less charged with iodine than 
the former. In general characters it is similar to chlorine. 
It is a soft, friable, opaque solid, of a bluish-black color, and 
metallic lustre. It has a pungent odor, an acrid taste, and 
stains the skin of a deep brownish color. It destroys to a cer¬ 
tain extent the vegetable colors. It is not very soluble in 
water ( 61 ), unless the water is impregnated with salt. In this 
case a larger quantity is dissolved. It is soluble in ether and 
alcohol. Its vapor is about eight and one half times heavier 
than air (sp. gr. 8*7), hence it will remain in a bottle in which 
it is volatilized, or it may be poured by inclining the bottle in 
a stream of red vapor, which becomes of a violet color when 
less dense. 

Potassium and sodium, and several other bodies, burn in 
iodine. It is therefore regarded as a supporter of combustion , 
although its agency in promoting combustion is exceedingly 
limited. ( 62 ) 

135. One of the most characteristic properties of iodine is 
the production of a splendid blue color with starch. The 
iodine for this purpose must be free or uncombined, and the 
solution of starch cold. To set free the iodine when com¬ 
bined, it is merely necessary to add chlorine water or nitric 
acid, which takes the base, and if this be done in a solution 
of starch, the blue color is instantly produced. By this test 
iodine may be detected in water containing the 40, Vo o’ part. 
If a little iodine tincture be dropped upon flour, potatoes, &c., 
the presence of starch in these substances will be at once in¬ 
dicated. 

Iodine is consumed in large quantities in medicine. It is 
employed as pure iodine, and as iodide of potassium, but if not 
administered cautiously, and in very small quantities, it is an 
irritant poison. The vapor of iodine is employed in rendering 
daguerreotype pictures sensitive to light, as will be explained 
hereafter. 


135. What is one of the most characteristic properties of iodine 1 In what 
state must the iodine be to give a blue color with starch ? How may it be dis¬ 
engaged if combined 1 What is the blue compound thus produced ?—Ans. 
The iodide of starch. What is said of the delicacy of this test for iodine ? What 
are some of the uses of iodine •? 



88 


ELEMENTS OF CHEMISTRY. 


Solutions of iodine are precipitated yellow by the salts of 
lead, red by the per-salts of mercury, and green by the proto¬ 
salts. A mixture of the sulphate of copper and sulphurous 
acid produces a yellowish-white precipitate (prot-iodide of cop¬ 
per) in solutions of alkaline iodides. 


BROMINE. 

136. Bromine is found in very minute quantities in sea¬ 
water, and in the ashes of certain medicinal plants. It is a 
brownish red liquid (the only element besides mercury which 
is liquid at the ordinary temperature) of a powerful and suffo¬ 
cating odor, emitting red fumes. This vapor is about six times 
as heavy as air (sp. gr. 5-93). Sulphuric acid floats on the 
surface of bromine, and is used to prevent its escape. It 
freezes at zero into a brittle solid. It causes phosphorus to 
burn, and combines with many metals with ignition. The 
flame of a burning taper, immersed in the vapor of bromine, 
appears red at the top and green below. It is therefore re¬ 
garded as a supporter of combustion , although most bodies are 
extinguished when immersed in it. It produces a yellow color , 
with starch. 

Both bromine and iodine are the constant attendants of 
chlorine ; wherever common salt occurs, whether in the earth, 
the sea, or in mineral springs, small quantities of these bodies 
are found, not in a free state, but combined with metals. The 
different sea-weeds attract these combinations from sea-water, 
and from these sea-weeds iodine and bromine are extracted. 
Both these bodies have poisonous properties. One drop of 
bromine administered to a bird, through the beak, is sufficient 
to cause death. A small quantity of bromine imparts a tran¬ 
sient yellow color to the skin ; a larger quantity produces a 
yellow and then a brown color, which can be removed only 
with the skin itself. In still larger quantity it produces im¬ 
mediate corrosion of the part to which it is applied, and violent 
inflammation. It corrodes also wood, cork, and other organic 
substances, imparting a yellow color to them. Like chlorine, 
it rapidly bleaches tincture of litmus and indigo. 


136. Where is bromine found ? What are some of its properties ? What 
is the specific gravity of its vapor ? What is used to prevent its escape ? At 
what temperature does it become solid? Why is bromine called a supporter 
of combustion ? What is said of the origin of bromine and iodine ? What is 
said of their poisonous and corrosive properties? Does bromine possess 
bleaching properties ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


89 


FLUORINE. 

137. It is doubtful whether fluorine has ever been obtained 
in a separate state. Its compounds can easily be decomposed, 
but its remarkable energy of combination with the metals, and 
especially with silicon, a constituent of glass, has rendered its 
isolation very difficult. When one of its compounds is decom¬ 
posed, it passes almost instantly into some other, and cannot 
be retained in the free state. It has been, however, proved to 
be a gas of a yellowish brown color, having the smell and 
bleaching properties of chlorine. It probably holds an inter¬ 
mediate place between oxygen and chlorine. 

Fluorine is very widely diffused, though in minute quanti¬ 
ties. It exists in the waters of the ocean, in many spring 
waters, and is also found in the blood and milk of animals 

Symbols and combining numbers of the halogens : 


Chlorine, 

Cl. 

35. 

Iodine, 

I. 

127 (126*57). 

Bromine, 

Br. 

78. 

Fluorine, 

F. 

19. 


These substances have a far greater affinity for hydrogen 
than for oxygen. With hydrogen they form acids (hydrogen 
acids), and with the metals salts, which are called haloid salts, 
to distinguish them from the common or oxygen salts. 


SILICON AND BORON. 

138. Both of these substances occur in nature only in com¬ 
bination with oxygen; boron, but seldom, as in boracic acid, 
or borax, and silicon very abundantly, as in sand, quartz, and 
almost all kinds of stones. 

Silicon has a nut-brown color. Heated in the air it burns, 
but it is never more than partially converted into silica. It 
also burns when heated in the vapor of sulphur, and in chlo¬ 
rine. No other elementary substance is so changed by heat, 
by which it is converted into a darker, more dense, allotropic 


137. Why is it difficult to obtain fluorine in a free state ? What are some of 
its properties? Between what two gases is it supposed to belong? Write 
the symbols and combining numbers of the halogens. What kind of acids do 
these elements form ? What are their salts called ? Why are they so called ? 

138. What are the sources of silicon and boron ? Do they ever occur except 
in combination with oxygen ? What are some of the properties of silicon ? 
How do the two forms of silicon differ from each other ? How may the second 



90 


ELEMENTS OF CHEMISTRY. 


form, insoluble and incombustible even under the oxy-hydrogen 
blowpipe. (183.) This change in its properties takes place when 
heated without contact of air , or in a covered crucible. 

Boron is a dull greenish-brown powder. When heated in 
the air, or in oxygen, it bums with a vivid light, scintillating 
powerfully, and forms by its combustion boracic acid. It is 
at once attacked by nitric acid, chlorine, alkalies in a fused 
condition, and other agents. When mixed with saltpetre and 
heated, it explodes. 

Symbols and combining numbers of the hyalogens : 

Silicon, Si. 22. 

Boron, B. 11. 


ACID COMPOUNDS OF THE NON-METALLIC 
ELEMENTS. 

139. The compounas of the non-metallic elements may be 
divided into acids, neutral bodies, and bases. By the term acid 
is meant a substance that is sour, reddens vegetable blues, ( 5S ) 
and neutralizes or destroys the properties of the bases. ( M ) Bases 
include alkalies and metallic oxides. Alkalies are those sub¬ 
stances that have an acrid taste and caustic properties ; that 
change vegetable blue infusions to green, or yellow to brown, 
and that neutralize acids*. ( 55 ) Neutral substances are those 
which possess neither the properties of acids nor bases, and 
are sometimes produced by the action of acids on bases, by 
which the peculiar properties of each component are destroyed 
in the resulting compound. These substances are called salts, 
and form a very important class of bodies. ( 56 ) 

The above division of bodies into acids, neutral bodies, and 
bases, is very convenient on account of the marked distinction 
between these classes of bodies. It should, however, be borne 
in mind that this classification is not perfect, as there are some 
bodies which act the part of bases to strong acids, and of acids 
to strong bases.* 

* In the same way the classification of bodies into metallic and non-metallic 
which is universally adopted, is not free from objection, as there are some 
bodies possessing properties common to both classes. 


form be produced from the first ? What are some of the properties of boron ? 
Write the symbols and combining numbers of the hyalogens. 

139. In what manner may the compounds of the non-metallic elements be 
divided ? What is meant by the term acid ? What do bases include ? What 
is meant by the term alkali ? What is a neutral substance ? 




THE ELEMENTS AND THEIR COMBINATIONS. 


91 


140. The most important of the acid compounds of the non- 
metallic elements are, sulphurous and sulphuric, nitrous and 
nitric, phosphorous and phosphoric, carbonic, hydro-chloric, 
chlorous and chloric, hydrosulphuric or sulphuretted hydrogen, 
hydrofluoric, and silicic. 


Sulphur. Oxygen. 

Sulphurous acid, 16 16 

Sulphuric acid, 16 24 


Symbol. 



141. Sulphurous add is found in the neighborhood of vol¬ 
canoes, both in the gaseous state and in springs. It is the only 
product of the combustion of sulphur in the air, or in oxygen 
gas. It is most conveniently prepared by heating copper clip¬ 
pings, or metallic mercury, with sulphuric acid in a retort. 
The copper, or mercury, decomposes the sulphuric acid, taking 
one third of its oxygen, and the sulphuric acid becomes sul¬ 
phurous. In symbols , from S0 3 (sulphuric acid) take 0, there 
remains S0 2 (sulphurous acid). 


Sulphuric 

acid, 

Copper,— 


) 2 oxygen- 
> sulphur • • 
) oxygen 


Sulphuric acid- 


‘Sulphurous 

[passes off in gas.] 


ACID. 


-oxide of copper. 


[unites with sulphuric acid to form sulph. of copper.] 

-sulphate of copper, soluble salt. 

[remains in solution.] 


142. Sulphurous acid is a colorless gas, having the peculiar 
suffocating odor of burning brimstone. It is acid in its taste, 
and reddens litmus paper, or vegetable blues. It has the 
power of checking vinous fermentation, and it is therefore em¬ 
ployed in the process of brewing and mixing wine. It also 
possesses bleaching properties. Litmus paper after being red¬ 
dened by the acid fumes, is slowly bleached. ( 67 ) The fumes 
of burning sulphur are employed to whiten straw and to bleach 
silk, linen, and cotton. To the straw and the silk it imparts a 
peculiar gloss. The colors are not, however, destroyed , for they 
may, in general, be restored by the application of a stronger 
acid, or an alkali. Sbmetimes the action of the sulphurous acid 
is to remove oxygen from the coloring matter, and thus to leave 
a colorless compound. The same result is at other times ob- 


141. Write the composition and symbol of sulphurous acid ;—sulphuric acid. 
Where is sulphurous acid found in nature 1 How is it easily produced ? De¬ 
scribe the method by which it is prepared for experiment. 

142. What are some of the properties of sulphurous acid ? For what pur¬ 
poses is it sometimes employed ? Does it destroy vegetable colors perma- 






92 


ELEMENTS OF CHEMISTRY. 


tained by combining with the coloring matter. In some cases 
the action may be explained, by supposing that sulphurous 
acid decomposes water, withdrawing its oxygen, and leaving 
its hydrogen to combine with the coloring matter, and to form 
a colorless compound. Sulphurous acid extinguishes burning 
bodies. The burning soot of a foul chimney may be extin¬ 
guished by throwing sulphur on the fire, and thus filling the 
chimney with the fumes of sulphurous acid. It is speedily 
destructive to animals placed in it. (**) It is the easiest of all 
gases to condense into the liquidform, requiring for this pur¬ 
pose only to be passed in a dry state through a glass tube sur¬ 
rounded by a freezing mixture of snow and salt. The same 
effect may be produced by exerting on it a pressure of two at¬ 
mospheres while at the freezing point. 

Water at 60° is capable of dissolving nearly 50 times its 
volume of sulphurous acid, forming a strongly acid fluid. Its 
avidity for moisture is so great, that it forms an acid fog with 
the moisture of the atmosphere, and a bit of ice slipped under 
a jar of sulphurous acid is instantly melted and absorbs the gas, 
the mercury rising to fill the jar. 

143. Sulphurous acid is easily converted into sulphuric. 
All that is required is the presence of oxygen gas and water. 
A mixture of sulphurous acid and oxygen may be kept for a 
long time over mercury without chemical action : but if water 
be admitted, sulphurous acid gradually unites with the oxygen, 
and is converted into sulphuric acid. This property of sul¬ 
phurous acid is of great importance, as on this the process for 
making sulphuric acid, on the large scale, depends. From its 
affinity for oxygen, sulphurous acid decomposes the solutions 
of those metals which have a weak affinity for oxygen, such 
as solutions of gold, silver, and mercury (with heat), and 
throws down these bodies in a metallic form. By nitric acid 
it is immediately oxidized and converted into sulphuric acid. 

144. Sulphuric acid. This is the most important of all the 
acids. It has all the acid properties in a high degree. When 
pure, it is a limpid colorless fluid, nearly twice as heavy as 
water. It boils at 62(4, and freezes at 15°. When combined 
with water, so that its specific gravity is 178. it freezes at as 

nently ? What effect does it produce on burning bodies ? How may a burn¬ 
ing chimney be extinguished ? What is its effect on animal life ? How is it 
condensed into the liquid form ? To what extent is sulphurous acid absorbed 
by water ? What is said of its avidity for moisture T 

143. What is necessary for die conversion of sulphurous acid into sulphuric ? 
By what experiment is this illustrated J What effect has sulphurous acid on 
solutions of metals which have a weak affinity for oxygen ? How does it de¬ 
compose these solutions ? In what form are the metals thrown down ! 

144. What are some of the properties of sulphuric acid ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


93 


high a temperature as 40°, but any further addition of either 
water or acid, causes the temperature of its freezing point to 
sink. 


145. The process for the manufacture of sulphuric acid is very impor¬ 
tant and instructive, but to understand it fully requires a knowledge of 
some bodies not yet described. If, however, at present it may not be 
intelligible, there will be no difficulty in understanding it on a review of 
this and a few following pages. The process is as follows— 

A and B are two furna¬ 
ces : C and D two gas chain- Fig. 61. 

bers.* From a boiler in A 
steam is produced, which 
passes through the pipe g into 
the chamber C. On the floor 
of the furnace B sulphur is 
strewn. This is set on fire, 
and the fumes thus produced 
are sulphurous acid (S0 2 ), which pass through the chimney b, into the 
chamber C. In the furnace B is seen a tripod, and upon this an iron 
dish. This iron dish or capsule contains sulphuric acid and saltpetre. 
The flame of the sulphur beneath the capsule causes deutoxide of nitro¬ 
gen (N0 2 ) to be given off, from the decomposition of the saltpetre (ni¬ 
trate of potash). This also passes through the chimney b, and coming 
in contact with the oxygen of the air in the chamber G, it doubles its 
quantity of oxygen, and becomes N0 4 or hyponitric acid. But it also 
meets with watery vapor, from which it takes another portion of oxygen, 
and becomes N0 5 or nitric acid. In this form it acts upon the sulphur¬ 
ous acid S0 2 , causing it to pass to sulphuric acid S0 3 , while itself, losing 
oxygen by this process, returns to the state of hyponitric acid N0 4 . 
The entire process is represented in the following diagram— 



Cl) 


C?) 


no 2 


20 


(4) 




3H0^*N05 

W SOf-A 




NO* ,„N 

(8) (9) 

so = ♦ N04 (10) 

3HO—v'NOs ♦ NO* 


No. 1 in the diagram is the symbol for the deutoxide of nitrogen. 
This unites with no. 2, or two atoms of oxygen from the air in the cham¬ 
ber C, and forms no. 3, or hyponitric acid N0 4 . This in the presence of 
water 3 HO no. 4, is converted into nitric acid NO s ho. 5, and deutoxide 
of nitrogen N0 2 no. 6. The nitric acid no. 5 acts upon the sulphurous 
acid S0 2 no. *7, and causes it to become sulphuric acid S0 3 no. 8, while 
itself, losing oxygen by this process, becomes again hyponitric acid N0 4 


* In some cases these chambers contain each 100,000 cubic feet, and are pro¬ 
vided with several steam-jets in different parts. The quantity of air which is 
admitted is measured and regulated by a register, the sulphurous acid is con¬ 
ducted by several pipes into different parts of the chamber, the design of all the 
arrangements being to insure, as far as possible, a perfect mixture of the gases 
and watery vapor, and the formation of sulphuric acid, before the watery vapor 
condenses. 


















94 


ELEMENTS OF CHEMISTRY. 


no. 9. This with water (as before, nos. 3 and 4) becomes nitric acid and 
deutoxide of nitrogen, as in nos. 5 and 6 ; and thus the process is repeat¬ 
ed indefinitely. Moreover the deutoxide of nitrogen no. 6 and no. 10 
repeats the entire process as given in the diagram from no. 1. 

When the gases are in excess in C, they pass into a second chamber 
D, <fcc. The acid collects on the floor of these chambers. When it has 
attained a certain degree of strength, which is regulated by admitting 
more or less steam into the chambers, it is drawn off and concentrated by 
evaporation; first, in leaden pans, and afterwards in stills of platinum, 
until it attains a specific gravity of about T84. It is then transferred 
into carboys, or large glass -bottles fitted into baskets, and is ready for 
sale. In Great Britain the manufacture of sulphuric acid is one of great 
and rapidly increasing national importance, and is carried on to a vast 
extent. 

146. The attraction of sulphuric acid for many bases is such, 
that it separates and expels all other acids from their combina¬ 
tions^ 59 ) Its affinity for water is so great, that it absorbs 
fifteen times its weight from the atmosphere. When dilute 
acid is boiled, pure water is given off at first, and no acid vapor 
mixes with the vapor of water till it is brought to the propor¬ 
tion of 2 atoms of water to 1 of acid, when the acid evaporates 
unchanged. When mixed with water, the volume of the mix¬ 
ture is condensed, and its temperature rises above the boiling 
point of water,* so that water placed in a small test tube, in 
this mixture, boils ; a test tube containing alcohol, or ether, 
will boil more violently.( eo ) 

A contrary effect is produced by adding sulphuric acid to 
snow.f The most intense cold is instantly produced by the 
sudden change of the snow to the liquid form of water. Water 
added to snow dissolves it but gradually, but the acid melts a 
large quantity at once, and the great amount of heat which 
thus becomes latent, is absorbed from the bodies with which 
the snow is in contact. 

147. Sulphuric acid in contact with wood causes (by dispos¬ 
ing affinity p. 60) its oxygen and hydrogen to unite and form 
water, with which it combines. The carbon of the wood with 

* Three parts in 100, is the maximum condensation, and the maximum heat 
is obtained when 500»grs. of acid are mixed with 150 grs. of water. 

t One part of sulphuric acid with one part of snow, evolves heat: with one 
and one quarter parts of snow, no change of temperature occurs, and with a 
larger quantity intense cold is produced. 


146. What is said of the attraction of sulphuric acid for the bases of salts? 
What is said of its affinity for water 1 What takes place when water is added 
to sulphuric acid ? Ans.—The volume of the two substances is diminished and 
the temperature rises above the boiling point of water. What effect is produ¬ 
ced by adding sulphuric acid to snow ? To what is the intense cold of this 
mixture owing ? 

147. What is the action of sulphuric acid on animal and vegetable substances ? 
Why is wood blackened and charred by sulphuric acid ? What tests are em- 




THE ELEMENTS AND THEIR COMBINATIONS. 


95 


a portion of its hydrogen and oxygen remain, forming a 
brownish-black compound, which gives to the wood the appear¬ 
ance of being charred by fire. It destroys also most vegetable 
and animal substances. In the refining of burning oil, the 
slime of the oil is charred by sulphuric acid. 

Sulphuric acid may be detected in exceedingly small quan¬ 
tities by any of the soluble salts ol barium. If a few drops of 
the acid he added to a test tube, or a wine glass of water, and 
a little baryta water he added, a dense white precipitate is 
formed. Every 100 grains of this precipitate indicate 34 grains 
of sulphuric acid. Water containing the T „ olo o o P art of sul¬ 
phuric acid, is rendered slightly turbid by the addition of ni¬ 
trate of baryta; and water containing the ^ookoo P art > is 
slightly clouded after the lapse of 15 or 20 minutes. 

148. If a meadow or field be irrigated with one pound of 
sulphuric acid, diluted with 100 pounds of water, the soil will 
be rendered more fertile and productive. The sulphuric acid 
acts to decompose and render soluble several kinds of earth, 
and the soluble sulphates thus formed are absorbed by the 
plants, and accelerate their growth. If only 10 times diluted, 
sulphuric acid has the contrary effect, and may serve for 
destroying grass, and weeds in alleys, &c. 

Sulphuric acid exists combined with the water of certain 
volcanic springs. It is found in large quantities, both in the 
organic and inorganic kingdoms. 



Nitrogen. 

Oxygen. 

Symbol. 

Nitrous acid, 

14*06 

24 

NO„ 

Hyponitric acid, 

14-06 

32 

no 4 . 

Nitric acid, 

14-06 

40 

no 5 . 


149. Nitrous acid is obtained by the action of nitric acid, 
diluted with about two parts of water, on metallic copper, 
with the presence of air , from which oxygen is absorbed dur¬ 
ing the process. 


Nitric acid, 


Copper- 

Nitric acid- 


oxygen 
nitrogen *' 
oxygen 


•Nitrous acid. 

[passes off as gas.] 


vs——oxide of copper. 

[unites with nitric acid.] 

‘nitrate of copper, soluble salt. 

[remains in solution.] 


i ployed to detect sulphuric acid ? How much sulphuric acid is indicated by 100 
grains of its precipitate with baryta? What is said of the delicacy of the test 
with nitrate of baryta ? 

148. Why is a very weak solution of sulphuric acid favorable to the growth 
of plants ? What effect has a strong solution ? Where is sulphuric acid found ? 

149. Write the composition and symbols of nitrous, hyponitric, and nitric 









96 


ELEMENTS OF CHEMISTRY. 


The gas is copiously evolved, and may he collected in dry 
vessels by the displacement of air. It has a characteristic 
orange red color. It cannot he breathed, and excites great ir¬ 
ritation in the throat and lungs, even when diluted with air. 
Bodies which burn with great intensity, as phosphorus, de¬ 
compose this gas, and therefore their combustion is continued 
by the great amount of oxygen which it contains. Ignited 
charcoal produces the same effect, but a taper, or burning sul¬ 
phur, will be extinguished. Its density is 1*451, air being 
1,000 ; it is therefore about one half heavier than air. The 
power of water to absorb this gas, may be shown while the 
gas is collecting, by stopping the neck of the receiver around 
the glass tube with wet cotton or sponge. Even after the re¬ 
ceiver is full of gas, none will escape into the room, the excess 
being absorbed by the wet cotton.( 61 ) Nitrous acid destroys 
life. An animal dropped into this gas instantly dies. 

The relations of nitrous acid to light are very remarkable. 
When its temperature is very low it is nearly colorless, but it 
takes an orange tint as the degree of heat increases, and finally 
becomes almost black. If it is examined while undergoing 
these changes, by passing a ray of light through it, and analyz¬ 
ing the ray by means of a prism, a great number of dark lines 
are found in the resulting spectrum ; as the temperature rises, 
these increase so much in number and in breadth, that the light 
finally becomes obliterated. 

150. Nitric acid is the most important compound of oxygen 
and nitrogen. When pure it is perfectly colorless, but when 
exposed to the rays of the sun it becomes yellow from partial 
decomposition, and, on loosening the stopper of the bottle, it is 
projected with force by the gas produced by decomposition. 
To preserve the acid colorless, it must be kept in a covered 
bottle. ( 82 ) The yellow color may be driven off by heat, and 
it becomes again colorless, but too great heat decomposes the 
acid. If vapors of nitric acid are passed through a porcelain 
tube strongly heated, they are completely decomposed into oxy¬ 
gen and nitrogen. If the tube is less heated, oxygen and 
hypo-nitric acid are produced. It is intensely corrosive and 
sour, and fumes when exposed to the air. It is one half heavier 
than water (sp. gr. T51). Its action on metallic and other 


acids. Explain the method of obtaining nitrous acid. What are some of its 
properties ? What bodies burn in nitrous acid ? What other properties of ni¬ 
trous acid are mentioned ? What is its effect on animal life ? What is said of 
its relations to light ? 

150. What are some of the properties of nitric acid ? In what manner may 
this acid be preserved colorless ? How may its yellow color be driven off ? 
What is said of its action on metallic and other combustible bodies? What is 



THE ELEMENTS AND THEIR COMBINATIONS. 


97 


combustible bodies is exceedingly violent, owing to the great 
amount of oxygen which it contains. A little water must, how¬ 
ever, be present in the acid, as very strong acid seems to have 
but little power in this respect. Organic substances, also, as 
sugar and starch, decompose with nitric acid and cause an - 
evolution of abundance of red fumes. ( 63 ) In a dilute state it 
stains the skin and nails, and many other animal substances, 
of a permanent yellow color, and is, for this reason, used to 
produce yellow patterns upon woollen fabrics. It boils at 248°, 
and freezes at about 40° below zero. When diluted with half 
its weight of water it becomes solid at 12° below zero, and 
with a little more water its freezing point is again lowered to 
—45°. It causes ice and snow suddenly to melt, producing in¬ 
tense eold. Hence this is one of the most common freezing 
mixtures. It will sink the thermometer from 12° above to 
30° below zero. 

Nitric acid has so strong an affinity for water, that, it is only 
recently that chemists have been able to obtain it uncom¬ 
bined with water, or isolated. It attracts moisture from damp 
air, and increases in weight. When suddenly mixed with three 
fourths its weight of water, it rises in temperature from 60° to 
140°. The large amount of oxygen which nitric acid contains 
it yields with great facility. It is, therefore, very useful to 
the chemist in processes for obtaining oxygen, or in imparting 
oxygen to other substances, as in the formation of several of 
the acids. Nearly all the metals are oxidized by it, and some 
of them with extreme violence; such as copper, mercury, and 
zinc, in the concentrated acid. It is mueh used in the arts by 
engravers for etching their copper plates, in the solution of ’ 
metals, and as a solvent for tin by dyers and calico-printers. 

It has also important uses in medicine. In its concentrated 
state it is a deadly poison, corroding and destroying the ani¬ 
mal organs. 

It cannot be detected by the precipitation of its compounds, 
since these are all soluble. One of the best tests is its power 
of bleaching sulphate of indigo, when boiled with that liquid, 
and copper filings ; to remove doubt from the result, it is ne¬ 
cessary to decide that chlorine is not present, whieh may be 
done by the tests for chlorine. The tint which nitric acid gives „ 
to hydrogen flame, is one of the means for detecting its pres- 


essential to this action ? What is its action on organic substances ? What 
other properties of nitric acid are mentioned? What is said of its affinity for 
water? What is meant by the phrase water of constitution? Ans—That 
water, without which the body cannot exist, or a separation from which is 
always attended by its decomposition. What is said of the relations of nitric 

5 




98 


ELEMENTS OF CHEMISTRY. 


ence. For this purpose a few fragments of zinc and sulphuric 
acid are added to the nitrate or the body supposed to contain 
nitric acid. If nitric acid be present, on setting fire to the hy¬ 
drogen formed from the zinc and sulphuric acid, a greenish 
tinge will be given to the flame. Another test for nitric acid 
is the formation of aqua regia* when hydrochloric acid is 
added to its solution. If this is formed by the addition of hy¬ 
drochloric acid, which may be determined by placing some 
gold leaf in the solution, nitric acid is present. 

Nitric acid forms transparent colorless crystals of great bril¬ 
liancy, having the form of prisms with six faces. (166.) When 
slowly deposited from a current of gas, they attain a consider¬ 
able size. They melt at a little above 85° and boil at 113°. 
When water is added they dissolve completely, causing a great 
rise of temperature. 

Combined with potash or soda, nitric acid is a very valuable 
fertilizer. When applied to young grass, or to the sprouting 
shoots of grain, it hastens and increases their growth. It also 
occasions a larger produce of grain, and this grain is more nu¬ 
tritious in its quality. When thrown on decomposing manure 
heaps, it unites with the ammonia which is evolved in such 
places, and forms nitrate of ammonia (225), a salt of great 
value to plants. 

Phosphorus. Oxygen Symbol. 

Phosphorous acid, 31.38 24 P0 3 

Phosphoric acid, 31.38 40 P0 5 . 

151. Phosphorous acid. The white fumes which arise from 
the slow combustion of phosphorus are phosphorous acid. It 
is also formed when phosphorus is burned in a very limited 
supply of air or oxygen gas. It is an acid of very little impor¬ 
tance. It forms white and very bulky masses, easily volatilized 
and sublimed, having a very strong affinity for water, which 
it absorbs, together with oxygen, from the air, and gradually 
becomes phosphoric acid. It has a garlic smell. Its solutions 
are sour, and it forms well determined salts. It is, therefore, 
strongly acid in its properties. On account of its strong affin¬ 
ity for oxygen, the solution of this acid is sometimes used as a 
deoxidizing agent. 

* A mixture of nitric and hydrochloric acid, which will dissolve gold and 
platinum. 


acid to oxygen? What uses are made of nitric acid l What are some of the 
tests for this substance 1 What is said of its use in agriculture ? 

151. Write the composition and symbols of phosphorous and phosphoric 
acids. How is phosphorous acid formed 1 What are some of its properties i 




THE ELEMENTS AND THEIR COMBINATIONS. 


99 


152. Phosphoric acid. The method by which nitrogen and 
phosphoric acid are prepared at the same time, has been de¬ 
scribed under the head of nitrogen. (102.) If it be collected 
from the inside of a jar in which it is formed, and quickly 
put into a dry watch-glass, and a few drops of water be 
added to it, the water and the acid will combine with ex¬ 
plosive violence, producing great heat, accompanied by a hiss¬ 
ing sound. Once in a state of hydrate, the water cannot again 
be separated from it. This acid is not poisonous, neither does 
it corrode the skin. At a high furnace heat, charcoal decom¬ 
poses phosphoric acid by abstracting its oxygen, and the phos¬ 
phorus sublimes. This may be collected by immersing the 
neck of the retort under water. 

Phosphoric acid is of great value in agriculture. It is an 
essential element in the constitution of most valuable plants, 
and one that by constant cultivation is generally first exhausted 
from the soil. The great requisite, therefore, of most soils 
which have been long cultivated is phosphoric acid, by supply¬ 
ing which to the manures which are applied to such soils their 
fertility may be very greatly increased, especially for grain 
crops, as wheat, oats, &c. 

Carbon. Oxygen. Symbol. 

Carbonic acid, 6 16 C0 2 . 


Fig. 52. 


153. For preparing carbonic acid, a wide-mouthed bottle, b, 
(Fig. 52,) is provided with a bent tube, c, passing through its 
cork, and a funnel tube, f. Pieces of white 
marble, or chalk, are placed in the bottle, 
which is then stopped, and a little water 
poured in through the funnel. When the 
end of the funnel tube is covered with wa¬ 
ter, hydrochloric acid is added, and the gas 
comes over and may be collected in dry 
bottles, as represented in the figure. A 
piece of pasteboard is placed over the bot¬ 
tle to prevent the agitation of the air from 
affecting the gas within. 



152. How is phosphoric acid produced ? What are some of its properties ? 

153. Write the composition and symbol of carbonic acid. Explain Fig. 52. 
What are some of the properties of carbonic acid ? At common temperatures 
and pressures how much carbonic acid does water absorb ? What effect does 
the presence of carbonic acid in mineral springs produce ?—in common water ? 
What are the relations of carbonic acid to combustion and life? What sub- 

















100 


ELEMENTS OF CHEMISTRY. 


Carbonate of 
lime, 

Hydrochloric 

acid. 


carbon- 

oxygen 

calcium- 

chlorine- 

°xygen--_ 

hydrogen- 


-Carbonic acid. 

[passes off in gas.] 

^chloride of calcium. 

[remains in solution.] 


-water. 


Carbonic acid is colorless and inodorous, and about a half 
heavier than air (sp. gr. 1-524). ( 64 ) Even when diluted with 
three times its volume of common air, it extinguishes a candle. 
By the pressure of 36 atmospheres, or 540 pounds to the square 
inch, it may be converted into a liquid. When the pressure 
is removed, the liquid resumes the gaseous state with such 
rapidity as to freeze that which is left. This sudden expan¬ 
sion into the gaseous state absorbs so much sensible heat, or 
converts so much sensible heat into latent, that bodies with 
which it is in contact are reduced to a temperature of 148° 
below zero. 

At —85° carbonic acid is frozen into a white fiocculent 
mass, resembling snow, and compressible like that substance. 
When exposed to the air, the acid disappears in a few min¬ 
utes, and often leaves behind a small quantity of water, con¬ 
densed from the air by the cold. If the snow is touched with 
the finger, when resting on a smooth surface, it glides quickly 
forward, as if supported by a stratum of gas. A piece of solid 
carbonic acid pressed upon the skin of an animal stops the cir¬ 
culation at the point of contact by the cold which it produces, 
forms a white spot, and after fifteen seconds, a blister. If 
some of the snow is introduced into a capsule containing mer¬ 
cury, and wet with ether, the mercury is frozen solid, and can 
be hammered and drawn out like lead. If it is moistened 
with ether in a vacuum, a cold of —-174° may be obtained. 

At common temperatures and pressures, water absorbs its 
own volume of carbonic acid ; under a pressure of two atmos¬ 
pheres it absorbs twice its own volume, &c. ; it loses this again 
either by boiling or freezing, or by exposure in the vacuum of 
an air-pump. If water which has been strongly charged with 
carbonic acid is rapidly frozen by being surrounded with a 
mixture of snow and salt, its bulk is very greatly increased by 
the immense number of gas-bubbles, which are entangled in 
the freezing mass, so as to have more the appearance of snow 
than of ice. When ice thus frozen is melted the water is 


stance burns in carbonic acid 1 How does the combustion of potassium in car¬ 
bonic acid take place ? Describe the Grotto del Cane in Italy ? In what pro¬ 
cesses is carbonic acid produced 1 In what manner is bread rendered light ? 







THE ELEMENTS AND THEIR COMBINATIONS. 101 

found, by its taste and other properties, to have lost nearly the 
whole of its carbonic acid. It is found in mineral springs, to 
which it imparts their effervescence, and their slightly pungent 
taste. The insipid character of water recently boiled is owing 
to the absence of carbonic acid. It does not support combus¬ 
tion, and is hostile to life. ( 65 ) If three jars be placed alongside 
of each other, one containing carbonic acid, the second oxygen, 
and the third common air, a candle will be put out in the first, 
relighted in the second, and will burn as usual in the third. 
Ignited potassium, however, burns in carbonic acid by decom¬ 
posing the gas, taking the oxygen and depositing the carbon 
in a fine black powder. 

The Grotto del Cane,* in Italy, is a cave so called because 
a dog is used to show the effects of the carbonic acid within 
the cave. It is situated on the bank of a lake, and a stream 
of warm 'water flows from it, accompanied with vapor and 
smoke. Above the water, and on its surface, a stratum of car¬ 
bonic acid rolls out from the cave. Being heavier than air, 
this does not rise, and therefore a man may walk in the cave 
and experience no inconvenience, but a dog soon drops down 
and dies unless drawn out to the air. So perfectly distinct 
does the stream of gas flow out from the cave, and to a dis¬ 
tance beyond it, that the smoke above the current marks its 
course, and rises and falls with the inequalities of the ground. 

Carbonic acid is produced in all the processes of fermenta¬ 
tion, and it is this gas which gives the foam and life to beer 
and other fermented drinks. In raising bread, carbonic acid 
is generated by the fermentative process ; and in baking, this, 
becoming entangled in the dough, renders the bread light and 
porous. It is also produced in the. ground by the fermentation 
of animal and vegetable matter. This is the origin of the 
choke damp of wells. Many accidents have occurred from 
persons descending into such wells. Meeting with carbonic 
acid they are suffocated, and fall into the well. A candle 
should always be let down into a well before descending into 
it. If the candle goes out, the air of the well is charged with 
carbonic acid. Even if the candle does not go out, the air 
may be so contaminated with carbonic acid as to render it in- 

* Grotto of the dog. 


What is the choke damp of wells? How may its fatal effects be avoided? 
What is another source of carbonic acid ? Should charcoal or any other fuel 
ever be allowed to burn freely in a room ? How may carbonic acid be driven 
off from most of its bases ? How are the stalactites and other calcareous con¬ 
cretions of caverns formed ? How may the presence of carbonic acid be deter¬ 
mined ? 



102 


ELEMENTS OF CHEMISTRY. 


jurious if breathed for a long time. This gas may be re¬ 
moved from wells by lowering down a quantity of recently ig¬ 
nited charcoal, or .quicklime mixed with water. It may also 
be pumped out by a pump furnished with a leather hose. 

Carbonic acid is one of the products of the combustion of our 
fires. As this, and all the other gases given off in combustion, 
are deadly in their nature, great care should be taken that 
none of the fumes from stoves or fire-places escape in the room. 
When charcoal is burnt, it should be under the draught of a 
chimney. Many persons have lost their lives from the fumes 
of charcoal burning freely in a room. 

The affinity of carbonic acid for most bases is so weak that 
it is driven off by heat. Lime is made in this way by roasting 
limestone (carbonate of lime), by which the carbonic acid is 
driven off, and caustic lime left. 

Carbonate of lime is soluble in water containing carbonic 
acid, but when the carbonic acid is driven off from such 
water, or diminished by heat or otherwise, the carbonate of 
lime is deposited. From this cause arise the vast calcareous 
deposits and concretions called stalactites, stalagmites, &c., 
which are found in caverns and similar places.( 66 ) 

The presence of carbonic acid is always determined by add¬ 
ing any other acid. If present it will be indicated by its 
effervescence, or by the sparkling appearance on the sides of 
the glass, or on the surface of the liquid. 

Plants obtain carbonic acid chiefly by absorption from the 
atmosphere, although much is also obtained from the soil. 
This is decomposed in the leaves by the direct rays of the sun, 
the oxygen is thrown back again into the atmosphere, while 
the carbon unites with the elements of water (oxygen and 
hydrogen) in the plant to form wood. The leaves which per¬ 
form this office for the plant, though of countless forms, from 
the spire of grass to the largest forest leaf, are all constructed 
with little mouths or absorbent pores, which drink in the car¬ 
bonic acid from the atmosphere. These pores are chiefly on 
the lower side of the leaf. The atmosphere contains about 
25 Vo' °f bulkof carbonic acid, or about seven tons over each 
acre. If half of this amount was withdrawn nearly all valua¬ 
ble plants would cease to flourish, and, in consequence, animal 
life would gradually become extinct. 

Hydrogen. Chlorine. Symbol. 

Hydrochloric acid, 1 00 35-41 HC1. 

154. This acid is formed by the action of dilute sulphuric 


154. Write the composition and symbol of hydrochloric acid. Explain the 




THE ELEMENTS AND THEIR COMBINATIONS. 


103 


acid on common salt. A little heat is applied, and the gas is 
collected in dry vessels by the displacement, of air. 


Chloride off chlorine- 
Sodium, ( sodium 

Water, \ hydrogen > 
( oxygen 

Sulphuric acid- 


Hydrochloric acid. 

{passes off in gas.] 


-oxide of sodium, soda. 

[unites with sulphuric acid.] 

-sulph. of soda, soluble salt. 

[remains in solution.] 


In the arts, hydrochloric acid is made in connection with 
other processes, particularly in the manufacture of carbonate 
of soda from common salt. It was formerly allowed to escape 
into the air, but it was found to produce such deleterious effects 
upon the vegetation and the animals in the vieinity, that it 
was required by law to be condensed. It was sometimes de¬ 
tected in the air at the distance of two miles from the manu¬ 
factory. Such quantities are now manufactured as greatly to 
reduce its price, and sometimes even to overstock the market. 

Hydrochloric acid may be produced by the direct union of 
its elements, or by synthesis. When equal measures of chlo¬ 
rine and hydrogen are mixed together, and an electric spark 
passed through the mixture, instantaneous combustion takes 
place, and hydrochloric acid is formed. Light also causes 
them to unite.( 6J ) If the mixture be placed in the direct rays 
of the sun, a sudden union of the chlorine and hydrogen takes 
place, attended with flame and explosion. The vivid galvanic 
light on charcoal points (83), produces the same effect. The 
mixed gases may also be exploded by a match. ( 68 ) 

When pure, hydrochloric acid is a colorless gas, with a pun¬ 
gent odor, and a sour taste. It is somewhat heavier than air 
(sp. gr. 1-269). By a pressure of 40 atmospheres, at 50°, it is 
condensed into a liquid of specific gravity 1-27. It cannot be 
breathed ; but when diluted with air it is far less irritating 
than chlorine. It extinguishes combustion, and is not itself 
combustible. One of the most* striking properties of hydro¬ 
chloric acid, is its great attraction for water. A white cloud 
appears whenever it escapes into the air, owing to its combin¬ 
ing with the invisible vapor of the air, and precipitating that 
vapor. A piece of ice put intp a jar full of this gas, disappears 
in a few moments, and if the jar stands over mercury, the 
water and the mercury rise in the jar to the top, the water of 
the melted ice absorbing the gas completely. On opening a 


process by which it is obtained. How is hydrochloric acid generally manufac¬ 
tured in the arts ? How may this acid be formed by synthesis ? What are 
some of its properties ? Mention some of the properties of liquid hydrochloric 








104 


ELEMENTS OF CHEMISTRY. 


wide-mouthed jar of hydrochloric acid underwater, the absorp¬ 
tion of the gas takes place so instantaneously, that the water 
is forced up into the jar with the same violence as into a va¬ 
cuum. Heat is produced in this experiment by the condensa¬ 
tion of volume which the gas undergoes. At 32° water dis¬ 
solves 500 times its volume of hydrochloric acid gas. The 
solubility diminishes as the temperature of the water rises. 
At 68° no more than 460 times its volume is dissolved in the 
water. 

Liquid hydrochloric acid, like the gas, is colorless when 
pure. It emits white vapors when exposed to the air, and 
possesses the acid properties in a high degree. Like sulphuric 
and nitric acids, when mixed with water it raises its tempera¬ 
ture by a condensation of volume. It boils at 110°, and 
freezes at 60° below zero. With nitric acid it forms aqua - 
regia . The properties of this compound are not those of the 
acid mixture, but of the chlorine which is set free, and which, 
in its nascent state (p. 60), dissolves gold and platinum. 

Hydrochloric acid is a valuable agent in medicine. Besides 
being used in the liquid form, like other medicines, it is used 
in the gaseous state as a disinfecting agent. For this purpose, 
it is common in hospitals and in other places of disease, to 
liberate the hydrochloric acid from common salt by means of 
sulphuric acid. In the arts it is used chiefly by the dyers in 
forming colors, and in obtaining chlorine gas (136.) for bleach¬ 
ing. It possesses also valuable antiseptic properties ( S3 ), and 
bleaching powers to some extent.( 70 ) In the laboratory it is 
very valuable in producing chlorine, in dissolving a great 
number of metals, and in testing for bodies in chemical 
analysis. ( 71 ) 

Chlorine . Oxygen. Symbol . 

Chlorous acid, 35-41 32 C10 4 . 

Chloric acid, 35 41 40 C10 5 . 

155. Chlorous acid is obtained by the action of sulphuric 
or hydrochloric acid on chlorate of potash. The chlorate of 
potash is made into a paste with sulphuric acid previously 
diluted with half its weight of water, and cooled ; this is in¬ 
troduced into a small glass retort, and very cautiously heated 
with warm water ; a deep yellow gas is evolved, whicli may 
be collected by displacement of air or over mercury. 


acid. How does aqua regia dissolve gold ? What are some of the uses of hy¬ 
drochloric acid ? 

155. Write the composition and symbols of chlorous and chloric acids. Ex¬ 
plain the process for obtaining chlorous acid. What are some of the properties 
of this acid ? When sulphuric acid is dropped on a mixture of chlorate of 



THE ELEMENTS AND THEIR COMBINATIONS. 


105 


chlorine 
oxygen 

Chlorate j °£P n 
of potash, j chlonile 
potash— 

Sulphuric acid- 

Chlorous acid has a powerful odor, quite different from that 
of chlorine, which it resembles in color and density. Water 
dissolves five or six times its volume of this gas, assuming a 
golden yellow tint of considerable intensity. It is exceedingly 
explosive, being resolved with violence into its elements by a 
temperature short of the boiling point of water. A rag wet 
with the oil of turpentine at once explodes it. Phosphorus 
takes fire spontaneously in chlorous acid. Its specific gravity 
is not quite as great as that of chlorine, being 2-36, while that 
of chlorine is 2 47. It may be liquified by pressure. Water 
absorbs chlorous acid freely. The solution possesses bleaching 
properties. 

When a mixture of chlorate of potash and sugar is touched 
with a drop of sulphuric acid, it is instantly set on fire, the 
chlorous acid disengaged being decomposed by the sugar (which 
takes away its oxygen) with such violence that the latter is set 
on fire. If a piece of phosphorus and some chlorate of potash be 
placed in the bottom of a wine-glass, and the wine-glass filled up 
with water, the phosphorus may be fired beneath the water by 
pouring, through a long funnel tube, sulphuric acid upon the 
mixture. In this experiment the sulphuric acid produces 
heat, and evolves chlorous acid from the chlorate of potash, 
which sets fire to the phosphorus. The mixture, at the same 
time, becomes yellow, from the chlorous acid disengaged, and 
it also acquires the odor of that gas. If strong sulphuric 
acid be poured upon a small quantity of crystals of chlorate of 
potash in a wine-glass, a violent crackling is heard, and the 
glass is soon filled with the heavy yellow vapor of chlorous 
acid, which at once inflames a rag wet with turpentine, and 
produces a smart explosion. 

156. Chloric acid, is formed by adding dilute sulphuric acid 
to a solution of chlorate of baryta as long as it occasions a 


potash and sugar, why does the sugar take fire ? How may a mixture of phos¬ 
phorus and chlorate of potash be fired beneath water ? What effect is pro¬ 
duced by pouring strong sulphuric acid on chlorate of potash in a wine-glass ? 

156. Explain the process for preparing chloric acid. Mention some of the 
properties of chloric acid ? In what way may the chlorates be detected 1 

5* 


.Chlorous acid. 

[passes off as gas.] 

'hyperchloric acid, (C1.0 g ). 

[unites with potash.] 

-hyperchlorate of potash. 

[dissolved in sulphuric acid.] 

■sulphuric acid solution. 










106 


ELEMENTS OF CHEMISTRY. 


precipitate. This precipitate is suffered to subside, and the 
liquid contains chloric acid in solution. 

f ) chlorine- •.••Chloric acid. 

Sulphuric acid-——^sulph. of baryta, insoluble salt. 

[precipitated from solution.] 

The clear liquid, containing chloric acid, may be poured off 
and carefully condensed by evaporation. In this state, its af¬ 
finity for combustible matter is so great, that it immediately 
inflames any substance containing carbon or hydrogen, with 
which in comes in contact. Like nitric acid, it cannot be 
isolated from water or a fixed base. The compounds of chloric 
acid, or the chlorates, are easily recognized. They give no 
precipitate with nitrate of baryta or silver. They also evolve 
pure oxygen when heated, and deflagrate on charcoal. When 
treated with sulphuric acid they evolve chlorous acid. 

Hydrogen. Sulphur. Symbol. 

Hydrosulphuric acid, TOO 16'00 HS. 

157. This gas is also called sulphuretted hydrogen. There 
are two methods by which it can be readily prepared. In the 
first, dilute sulphuric acid and sqlphuret of iron are employed ; 
in the second, hydrochloric acid and the sulphuret of antimony. 
The first process yields the gas most easily, the second in the 
purest state. 

Protosulphuret of iron is put into the apparatus used for 
carbonic acid (Fig. 52). Water is poured in through the fun¬ 
nel tube,/*, sufficient to cover the bottom of the tube ; sul¬ 
phuric acid is then added until a copious disengagement of gas 
takes place through the tube, c, which may be collected in a 
bottle partly filled with water. 

Sulphuret ( sulphur . Sulphuretted hydrogen. 

of iron, ( iron-- s . • • * , fP“ se " 

Water \ h y dr °g en \ 

’ ( oxygen--oxide of iron. 

[unites with sulphuric acid,] 

Sulphuric acid-sulphate of iron, soluble salt. 

[remains in solution.] 

The same arrangement may be employed to generate sul- 


157. Write the composition and symbol of hydrosulphuric acid. By what 
other name is this acid called ? Explain the first method for preparing hydro- 








THE ELEMENTS AND THEIR COMBINATIONS. 


107 


phuretted hydrogen by the second process. A flask should be 
substituted for the bottle, as heat is to be applied. 

Hydrochloric ( hydrogen -■.* Sulphuretted hydrogen. 

acid, ( chlorine^ . [passesoff as gu.] 

Sulphuret of] sulphur''* s N y 

antimony, 1 antimony —^.chloride of antimony, sol. salt. 

v J [remains in solution.] 

Sulphuretted hydrogen is a colorless gas, of a strong and 
very nauseous odor. This smell is perceived in the water of 
sulphurous springs, where this gas is formed abundantly. It 
is also formed when wet coal is thrown on the fire. # It is 
a little heavier than air (sp. gr. 1-171). f' 2 ) It has feeble 
acid properties. Under a pressure of 17 atmospheres, at 50°, 
it becomes a highly limpid colorless liquid of specific gravity 
0 9. At —122° it is frozen into a white crystalline translucent 
substance which is heavier than the liquid. To animal life it 
is very injurious. Birds perished in air containing only T J ¥¥ , 
and a dog in air containing T | ¥ of this gas. A horse died in 
an atmosphere containing only the part. It is owing to 
this fact that localities where this gas rises are unhealthy. 
Recent experiments show that the waters of some African 
rivers, whose mouths are remarkably unhealthy, contain this 
gas in considerable quantity. In this case the sulphuretted 
hydrogen arises from the mixture of the waters of the sea, 
which contain salts of sulphuric acid, with the river water 
which is charged with organic matter. This formation of sul¬ 
phuretted hydrogen sometimes extends to a distance of twenty- 
seven miles from the mouths of the river. The water contains 
sometimes as much as six cubic inches of sulphuretted hydrogen 
in a gallon. The copper sheathing of ships is very rapidly 
corroded in this water, and the crews are attacked with malig¬ 
nant fevers. 

Water at 64° dissolves 2\ volumes of sulphuretted hydro¬ 
gen, and alcohol 6 volumes. These solutions soon become 
milky when exposed to air, the oxygen of which combines 

* This gas is also found in foul sewers and putrid eggs, to which they, espe¬ 
cially the latter, owe their peculiarly offensive smell. The water of sulphur¬ 
ous springs rarely contains more than one and one half per cent, of its volume 
of this gas. 


sulphuric acid—the second. Mention some of the properties of sulphuretted 
hydrogen. What are its relations to animal life ? What is said of the waters 
of some African rivers ? To what is the presence of sulphuretted hydrogen in 
these waters owing ? How much hydrosulphuric acid does this water some¬ 
times contain 1 What effect has it upon the copper Sheathing of ships ?—upon 
the health of their crews ? What is said of the relations of hydrosulphuric acid 






108 


ELEMENTS OF CHEMISTRY. 


with the hydroge.ii of the gas and precipitates the sulphur. 
In the same way deposits of sulphur are formed in the neigh¬ 
borhood of mineral springs. In sulphurous acid and sulphu¬ 
retted hydrogen oxygen and hydrogen are united to the same 
base, sulphur; when, therefore, these two gases are brought 
together, in the moist state, they mutually decompose each 
other, the oxygen of the one taking the hydrogen of the other, 
and the sulphur of both being deposited. The vessel in which 
the two gases are mixed becomes coated with sulphur. In 
this experiment, the space between the tubes and the neck of 
the bottle in which the gases are mingled, should be stopped 
with loose cotton, or a tube open at both ends should pass 
through the cork, that there may be a free communication with 
the external air. 

The disinfectants which are employed in places where this 
gas rises, operate by decomposing it. Chlorine, iodine, and 
bromine, decompose it immediately by uniting with its hydro¬ 
gen, and depositing its sulphur. If either the chlorine, iodine 
or bromine are in excess, it combines with the sulphur forming 
a chloride, iodide or bromide of sulphur. The oxygen of the 
air does the same to a small extent, as mentioned above. 

A remarkable instance of an atmosphere fully charged with 
sulphuretted hydrogen being disinfected by hydrochloric acid 
gas, (p. 104.) occurred in France in 1773. A cathedral at 
Dijon, had become infected with putrid miasma from the 
bodies interred under the floor. Several unsuccessful attempts 
had been made to purify the air by explosions, aromatics, &c., 
until the building was finally deserted. Application having 
been made to Prof. Morveau, he took a glass vessel, supported 
by one of cast iron, and placed it on a few live coals in the 
middle of the church. He then put in six pounds of common 
salt, and two pounds of sulphuric acid, and hastily withdrew. 
The gas soon filled the vast space, and could be perceived even 
at the doors. At the end of twelve hours the church was 
thrown open and ventilated, when every disagreeable odor was 
found to be completely removed. 

Sulphuretted hydrogen takes fire when a candle is immersed 
in it, but the candle is put out, and most burning bodies are 
extinguished by it. But when potassium is heated in this gas, 


to water ?—to alcohol ? Why do these solutions soon become milky ? How 
do sulphurous acid and sulphuretted hydrogen decompose one another ? How 
do the disinfectants which are employed in places where this gas rises act ? In 
what manner was a cathedral at Dijon in France disinfected of putrid mias¬ 
ma ? What is said of the relations of sulphuretted hydrogen to combustion ? 
What substance burns in this gas with great energy ? What other bodies burn 
in sulphuretted hydrogen ? Into what are they converted ? Ans.—Into sul- 




TIIE ELEMENTS AND THEIR COMBINATIONS. 


109 


it burns with great energy, and is converted into a sulphuret 
of potassium. The hydrogen that remains after the sulphur is 
in this manner withdrawn by potassium, is equal in volume to 
the original gas. Tin and many other metals, when heated in 
sulphuretted hydrogen, combine with its sulphur with flame. 
Sulphuretted hydrogen burns with a beautiful pale blue flame, 
producing water and sulphurous acid, part of the sulphur being 
deposited. ( 73 ) Two volumes of sulphuretted hydrogen to three 
of oxygen form an explosive mixture. A little strong nitric 
acid thrown into a bottle of this gas occasions the immediate 
oxidation of its hydrogen, and often a slight explosion, when 
the escape of the vapor is impeded. 

Sulphuretted hydrogen tarnishes certain metals, as gold, sil¬ 
ver, and brass ; hence utensils made of these metals should 
not be exposed to this gas. It also produces colored precipi¬ 
tates from many metallic solutions, and hence is constantly 
employed as a test in the laboratory. When diluted with 
20,000 measures of pure hydrogen, it sensibly blackens a piece 
of paper which has been dipped in a solution of acetate of 
lead.( 74 ) Letters formed with the nitrate or acetate of lead 
are invisible when the writing is dry, but are gradually brought 
out when the paper is held over a jar from which sulphuretted 
hydrogen is rising ; the sulphuretted hydrogen takes the base, 
forming sulphuret of lead, and drives off or sets free the acetic 
acid, if acetate of lead was employed, or the nitric acid, if the 
solution was one of nitrate of lead. Solution of sulphuretted 
hydrogen in water is the most common form in which this is 
applied as a test.( 75 ) 

A bright surface of silver is a sure test for the presence of 
sulphuretted hydrogen, which is instantly tarnished by this gas, 
and a black sulphuret of silver formed on its surface.( 76 ) The 
most delicate test of the presence of sulphuretted hydrogen, 
when diffused in the air, is moist carbonate of lead spread on 
white paper. 


pliurets. When potassium is burnt in sulphuretted hydrogen, how much 
hydrogen is liberated in volume 1 What is the color of the flame of sulphu¬ 
retted hydrogen ? What does it produce by its combustion ? How is water 
formed in this combustion ? Ans.—By the union of the oxygen of the air with 
the hydrogen of the sulphuretted hydrogen. How is the sulphurous acid 
formed ? Ans.—By the union of the oxygen of the air with the sulphur 
of the sulphuretted hydrogen. What is the effect of sulphuretted hydro¬ 
gen on certain metals ?—on many metallic solutions ? For what purpose 
is it employed in the laboratory ? What illustration is given of the delicacy 
of this test ? How may letters formed with the nitrate of acetate of lead be 
rendered visible 1 Why do these letters become black on holding them over a 
jet of sulphuretted hydrogen 1 What is the most common form in which the 
test with sulphuretted hydrogen is employed ? What are some of the tests for 
the presence of sulphuretted hydrogen ? 



110 


ELEMENTS OF CHEMISTRY. 


Hydrogen. Fluorine. Symbols 

Hydrofluoric acid, LOO 19-00 HF. 

158. This acid is obtained by the decomposition of fluor¬ 
spar by strong sulphuric acid. This must be done in a retort 
of pure lead, silver, or platinum, and requires a gentle heat. 
The fluor-spar must be pure, and especially free from silica and 
the oxide of lead. 


‘Fluor-spar, or ( 
Fluoride of < 
Calcium, | 

Water, j 

Sulphuric acid 


fluorine 

calcium 



•Hydrofluoric acid. 

[passes off in gas.] 


oxide-of calcium, lime. 

[unites with sulphuric acid.] 

sulph. of lime, insolu. salt.* 

[precipitates from solution.] 


/ 


Hydrofluoric acid at 32° is condensed into a colorless fluid, 
with a density of 1-069: In this state it can be preserved, even 
at a temperature above 32°, in well-stopped bottles of silver 
or lead. Its avidity for water is extreme, and when brought 
into contact with it, the acid hisses like red-hot iron. It is the 
only liquid which dissolves, to any great extent, flint and glass. 
It cannot therefore be kept in glass vessels. It is often used 
to etch glass. For this purpose it is used in the laboratory for 
marking test bottles, and for designs on glass-plate, which are 
first traced through a coating of wax. The glass having been 
thus prepared, is placed over a vessel of lead in which there 
is an equal weight of fluor-spar and sulphuric acid. A gentle 
heat is applied to this vessel, and the hydrofluoric acid pro¬ 
duced from this mixture will attack the glass in the lines 
which have been traced through the wax. The operation is 
completed in a few minutes, and the glass is then removed and 
cleaned by a little warm oil of turpentine. Liquid hydrofluoric 
acid may be employed for the same purpose, but the etching is 
not so distinct as when vapor is used, for, in this case, the 
figures are as transparent as the rest of the glass. ( 77 ) 

Hydrofluoric acid possesses the acid properties in a very 
high degree. Its action on some of the metals is very power¬ 
ful. With potassium it unites with explosion, evolving light 
and heat. It attacks and dissolves certain bodies which no 
\ 

* This salt is very slightly soluble. 


158. Write the composition and symbol of hydrofluoric acid. Explain the 
process by which it is obtained. Mention some of its properties ;—some of its 
uses. What is said of the action of hydrofluoric acid with some of the metals ? 
What is its effect on the animal system ? Why may this gas be employed in 
the analysis of siliceous minerals 1 







THE ELEMENTS AND THEIR COMBINATIONS. 


Ill 


other acid can affect, such as silicon, zirconium, and colum- 
bium, forming fluates of these substances, and setting free its 
own hydrogen. It is a most dangerous substance to experi¬ 
ment with, as it attacks all animal substances with wonderful 
energy. The smallest drop of the concentrated acid produces 
ulceration and death when applied to the tongue of a dog. 
Its vapor, floating in the air, is very corrosive, and should he 
carefully avoided. If it falls, even in small spray, on the skin 
of the hand or any other part of the body, it produces a malig¬ 
nant ulcer, which is very difficult to cure. Any considerable 
quantity of it would prove fatal. Its property of dissolving 
silica affords a method of analyzing siliceous minerals. It 
readily pombines with the silica of these minerals, when in a 
state of fine powder, and still retains its elastic form, or passes 
off as hydrofluosilicic acid (p. 113). 

Silicon. Oxygen. Symbol. 

Silicic acid, 22' 18 24-00 Si0 3 . 


159. That which is commonly called flint, is in chemistry 
called silicic acid. We find it nearly pure in beryl, quartz, 
chalcedony, hornstone, jasper, rock-crystal, &c., which are 


Fig. 53 * 


Fig. 54.t Fig. 554 



Fig. 56.$ 



* 


but varieties of quartz. It is often beautifully crystallized in 
six-sided prisms and six-sided pyramids, and so transparent 
and beautifully colored that ornamental stones are often made 
from it The ornamental stones called Bohemian diamonds, 
are composed of quartz. Some of the forms of the crystals of 
quarts are represented in the preceding figures. 

* Obtuse rhombohedron. 

t Six-sided prism, terminated by six-sided pyramids. 

j Dodecahedron, or two six-sided pyramids joined base to base. 

$ The two pyramids separated from each other by the intervention of a very 
short six-sided prism. 


159. Write the composition and symbol of silicic acid. What are some of 
the sources of silicic acid ? 









112 


ELEMENTS OF CHEMISTRY. 


The red cornelian, the yellow topaz, the violet amethyst, the 
green jasper, the variegated agate and jasper, the opal and 
chalcedony, black flint, brown flint, and rose-colored quartz, 
consist almost entirely of silica ; their colors are derived chiefly 
from metallic oxides. 

160. Silica may be procured in sufficient purity for most 
purposes, by igniting specimens of rock-crystal, and throwing 
them while red hot into water, and then reducing them to 

powder. But to obtain this sub¬ 
stance in a state of complete pu¬ 
rity, a mixture of equal parts of 
fluor-spar (fluoride of calcium) 
and glass, both finely powdered, 
are put into a flask. (Fig. 57.) 
Upon this mixture, sulphuric acid 
is poured. A wide bent tube 
passes from the flask to the bot¬ 
tom of a glass jar, in which 
enough mercury is poured to cover 
the extremity of the tube. The 
jar is then about two thirds filled 
with water, and heat applied to 
the flask. The first effect of the 
action of the sulphuric acid on 
fluor-spar is the disengagement of hydrofluoric acid (166.) 
This, however, being in contact with the powdered glass, is de¬ 
composed, and water and fluoride of silicon formed. 


Fig. 57. 



Hydrofluoric 

acid, 

9 

Silica (glass,) 


fluorine . .••••'Fluoride of silicon. 

hydrogen t A £ as - See next diagram-] 

silicon S, '' s 
oxygen-^-water. 


Th q fluoride of silicon, escapes through the tube, and rises 
from the mercury into the water above. As the bubbles come 
in contact with the water, they are decomposed ; the fluoric 
acid unites with the water, and pure silica separates in the 
form of a beautiful gelatinous mass. This decomposition is 
represented by the following diagram : 


160. How may silica be procured in sufficient purity for most purposes ? 
Explain Fig. 57. How is fluoride of silicon obtained by the first diagram ? How 
is silica obtained by the second diagram? In what state is this silica? Ans. 
—In the state of a gelatinous hydrate. How may the water be expelled from 
this hydrate ? 























THE ELEMENTS AND THEIR COMBINATIONS. 


113 


Fluoride of 
Silicon, 


\ Si 


silicon 

fluorines 


Water, ° x > T S e “ 

( hydrogen 

Fluoride of silicon- 


■Silica. 

[remains undissolved as gelatinous silica.] 


-^hydrofluosilicic acid. 

[dissolved in the water.] 


The gelatinous silica may he removed from the water, and 
dried on a filter. A cloth filter is used for this purpose, and 
the silica, after being well washed on the filter* and dried, is 
heated to redness to expel the water. It is important in this 
experiment to keep the end of the tube so far beneath the sur¬ 
face of the mercury, that the bubbles of gas will not come in 
contact with the water until they have left the tube, otherwise 
the gelatinous silica formed at the mouth of the tube may en¬ 
tirely close it and prevent the passage of the gas. 

161. Pure silica is a very fine, white, tasteless powder, 
which feels rough and dry to the touch and is gritty between 
the teeth. It is infusible, except by the most powerful heat 
of the oxy-hydrogen blowpipe, or by galvanism. In a state 
of fusion, it may be drawn out into threads, like glass. If 
dropped in this state into water, it solidifies to a transparent 
mass, free from flaws, and remarkably hard and tough, so that 
it sustains the blow of a hammer without breaking. The 
same effect is therefore produced as when red-hot steel is 
plunged into water. Though not itself volatile, yet when 
steam is passed into a mass of silica, heated above the melt¬ 
ing point of cast iron, it is volatilized m large quantity, and 
deposited in the form of snow. Boracic acid (138,) volatilizes 
in a similar manner. 

Silica, unless recently precipitated, is not sensibly soluble in 
water and dilute acids. Although a very powerful acid, it 
does not usually manifest its acid properties on account of its 
insolubility. But when heated with the bases, especially 
with bases which are fusible, it exhibits powerful acid proper¬ 
ties and forms true salts (139.) When the proportion of base 
is considerable, the salts of silica are soluble, as those silicates 
of potash and soda, which are soluble in water. But ^here 
silicic acid is in excess, as in all the silicates which enter into 
the composition of glass, these silicates are insoluble. Under 
-high degrees of pressure and temperature, or by slow action 

* This process will be described in the latter part of the book. 


161. What are some of the properties of silica? What is said of its solu¬ 
bility in water and dilute acids ? Why does it notjisually manifest its acid 
properties ? How may these be developed ? When are the salts of silica 
soluble ? What silicates are insoluble ? 





114 


ELEMENTS OF CHEMISTRY. 


under ordinary pressure and temperature, a small portion of 
even these silicates is dissolved. 

162. Silicic acid is nearly three times as heavy as water, 
its specific gravity being 2 66. In the arts, it is employed 
chiefly as a component of glass. Every kind of glass is a sili¬ 
cate, and all its varieties are produced by different proportions 
in the constituents employed, or by the impurity of the mate¬ 
rials. Thus green bottle glass is made of impure river sand, 
and the most common kind of kelp or pearl ashes. The iron 
contained in the river sand, united with the impurities of the' 
alkali, gives this kind of glass its color. Crown glass, lor 
windows, is made of a purer alkali and a sand which is free 
from iron. Plate glass for mirrors is composed of sand and 
alkali in their purest state, and, in the formation of flint glass, 
besides these pure ingredients, a considerable quantity of 
litharge, or red lead, is employed. The black oxide of man¬ 
ganese is also used to render glass colorless and to improve its 
transparency. This it does by converting the protoxide of iron, 
which colors the glass of a deep green into the sesquioxide 
(267) which gives to the glass a slight yellow tint hardly per¬ 
ceptible. The manganese itself passes from the peroxide into 
the protoxide, which does not perceptibly color the glass unless, 
used in too large quantity. When the peroxide of manganese 
is in excess it is converted only into the sesquioxide which 
colors the glass violet.( 78 ) 

163. Almost all springs, as well as plants, contain small 
quantities of silicic acid. If we evaporate spring water we 
find silica in the insoluble residue, and if we bum a plant, silica 
remains in the ashes. Grasses and different sorts of grain are 
particularly rich in silica, and, for this reason, have been called 
siliceous plants. Silica is to these plants, what bones are to 
men, the substance to which the stalks owe their firmness. If 
the soil is deficient in soluble silica, the stalk will be so weak 
as to bend over. The horse-tail plant (Equisetum) contains so 
much silica that it may be used in polishing wood, horn, and 
some of the metals. ( 79 ) Many microscopic animals have sili¬ 
ceous coverings. 

The siliceous minerals, such as rock-crystal, quartz, chalce¬ 
dony, flint, &c., form a large part of the crust of the earth. Sil¬ 
ica also predominates in the principal rocky masses of the globe. 


162. What is the principal nse of silica in the arts? To what are the dif¬ 
ferent varieties of glass owing? What is the composition of green bottle 
glass 1 —crown glass ?—plate glass 1 —flint glass ? For what purpose is black 
oxide of manganese used in the manufacture of glass ? 

163. Mention some of the sources of silicic acid. What purpose does silica 

serve in the stalks of grasses ? . 




THE ELEMENTS AND THEIR COMBINATIONS. 


115 


164. The following table exhibits the composition, combin¬ 
ing numbers, and symbols, of those elements, and their com¬ 
pounds which have now been described.* 


SIMPLE ELEMENTS. 


Organogens. 
Oxygen O. 8. 

Hydrogen H. X. 

Nitrogen N. 14. 

Carbon C. 6. 


Pyrogens. 

Sulphur S. 16. 

Selenium Se. 40. 

Phosphorus P. 31. 


Halogens. 

Chlorine Cl. 35. 

Iodine I. 127. 

Bromine Br. 7 8. 

Fluorine F. 19. 


Hyalogens. 
Boron B. 11. 
Silicon Si. 22. 


ACID COMPOUNDS. 


1. OXYGEN ACIDS. 


Sulphur 

S. 

16 i 

1 Sulphurous acid 

S0 2 . 

Oxygen 

0. 

8 

} Sulphuric acid 

16+16=32. 

so 3 . 

Nitrogen 

N. 

14 i 

| Nitrous acid 

16+24=40. 

no 3 . 

Oxygen 

0. 

«i 

| Nitric acid 

14+24=38. 

no 5 . 

Phosphorus 

P. 

31 1 

1 Phosphorous acid 

14+40=54. 

P0 3 . 

Oxygen 

0. 


) Phosphoric acid 

31+24=55. 

P0 5 ; 

31+40=71. 

Carbon C. 6 ) 

>• Carbonic acid C0 2 . 

Oxygen 0. 8 ) 6-j-16=22. 

This table shows the connection of all these bodies with each other, 


serves also the very important purpose of a review of their composition, without 
which this would soon be forgotten, or retained so imperfectly as to be of no 
practical benefit. 


164. Write the composition and symbols of the organogens ;—the pyrogens; 
—the halogens ;—the hyalogens ;—the acid compounds of sulphur and oxygen , 
—the acid compounds of nitrogen and oxygen;—of phosphorus and oxygen ;— 
carbon and oxygen ;—chlorine and oxygen ;—silicon and oxygen. What are 
these acid compounds called ? Ans.—Oxygen acids. Write the composition 
and symbols of the hydrogen acids. 








116 


ELEMENTS OF CHEMISTRY. 


Oxygen 0. 8) Chloric acid 


Chlorine Cl. 35 ) Chlorous acid 


C10 4 . 

35+32=67. 

010 ,. 

35+40=75. 



Si0 3 . 

22+24=46. 


2. HYDROGEN ACIDS. 


Chlorine Cl. 35 


H Cl. 
1+35=36. 


[ Hydrochloric acid 



HS. 

1+16=17. 



HF. 

1+19=20. 


165. This table is founded upon the tenth law of affinity 
(p. 60). This law is, “ when a body, A, unites with other 
bodies, B and C, the proportion in which A unites with B and 
C, will represent the proportion in which they will unite with 
each other.” Thus in the above table let hydrogen be repre¬ 
sented by A, and let the other bodies with which hydrogen 
unites, be represented by B, C, &c. ; then the proportion in 
which hydrogen unites with these bodies, will represent the 
proportions in which they will unite with each other. Since 
A, or hydrogen, unites with B, or oxygen, in the proportion 
of 1 to 8 (forming water—) and also with C, or sulphur, 
as 1 to 16 (forming sulphuretted hydrogen—see table,) there¬ 
fore the compounds of sulphur and oxygen are as the numbers 
16 and 8. Thus sulphurous acid=S0 2 = 16 + 8 X 2. Sul¬ 
phuric acid=S0 3 r=:16 + 8x3. Should any new compound 
of sulphur and oxygen be discovered, the proportion of these 
two elements will be expressed by some multiples of the num¬ 
bers 16 and 8. If, therefore, any new compound should be 
sought for by experiment, the experiments would be in the 
following series, 16 X (1, 2, 3, 4, &c.,) for the sulphur, and 
8X(1> 2, 3, 4, &c.,) for the oxygen. Sometimes, however, 
what are called sesqui* compounds occur, a series of which as- 


* Latin sesqui, one and a half. 


165. Upon what law of affinity is this table founded 1 State this law. How 
is this law illustrated ? Why do the compounds of sulphur and oxygen unite 
with each other in the proportions represented by the numbers 16 and 8 ? In 
what series would any new compounds of sulphur and oxygen be sought for by 
experiment ? What is meant by the term “ sesqui compounds” 1 What is the 



THE ELEMENTS AND THEIR COMBINATIONS. 


117 


cend by the multiples 1, 1^, 2, 2^, 3, &c.; thus A unites 
with 1, 1%, 2, 2f, 3, proportions of B, or 2 A unites with 1, 
2, 3, 4, 5, 6, B. The idea conveyed by the first proportion of 
fractions is not strictly correct, for the atoms of matter are in¬ 
divisible. Half an atom of A cannot combine with an atom 
of B ; by multiplying this proportion by 2, we obtain the 
second, in which the fractions are avoided ; this, therefore, 
represents more correctly the method of combination among 
what are usually called sesqui compounds. 

The second part of the table gives the combining numbers 
of compound bodies. According to the eleventh law of affin¬ 
ity (p. 60,) the rule for compound bodies is, “ add together the 
numbers corresponding to the elements of t he compound body ; 
the sum will represent the proportion in which the compound 
enters into combination. Thus the combining number of 
sulphur is 16, that of oxygen 8, therefore that of sulphurous 
acid (S0 2 ) is 16+8x2=32, and that of sulphuric acid (SCL) 
is 16 + 8x3=40. 


NEUTRAL COMPOUNDS OF NON-METALLIC 
ELEMENTS. 

166. The neutral compounds of the non-metallic elements, 
or compounds which have neither acid or alkaline properties, 
are nitrous and nitric oxides, carbonic oxide, light carburetted 
hydrogen, olefiant gas, and phosphuretted hydrogen. 


Nitrogen. Oxygen. Symbol. 


\ COfUgCfC. IDtJULUUl 

14-06 8 NO. 

14-06 16 N0 3 . 


Nitrous oxide, 
Nitric oxide, 


167. Nitrous oxide, protoxide of nitrogen. When nitrate 
of ammonia is exposed to a moderate heat, in a glass flask or 
retort, nitrous oxide is driven off and may be collected over 
warm water, or in water previously saturated with the same 
gas. The nitrate of ammonia should not fill more than a 
quarter of the retort as it is very apt to foam. Too much heat 


true series by which this class of compounds are represented ? Ans.—1, 2, 3, 
4, 5, 6, of B, to 2, 4, 6, 8, 10, 12, of A. Upon what law of affinity, is the second 
part of the table founded ? State this law. How is this law illustrated ? 

167. Write the composition and symbols of nitrous and nitric oxides. How 
is nitrous oxide prepared ? Explain the diagram. Mention some of the prop- 




118 


ELEMENTS OF CHEMISTRY. 


decomposes the nitrous oxide, and forms nitric oxide and nitrous 
acid’. The nitrate of ammonia, which, by heat alone, gives 
off nitric oxide, is composed of nitric acid, ammonia, and water 
(of crystallization). 


Nitric acid, 


Ammonia, 


nitrogen . Nitrous oxide. 

oxygen.‘ 

oxygen-... 

3 oxygen^ , 

nitrogen- - • .**.•»■ Nitrous oxide. 

N v [passes off as gas.] 

3 hydrogen-1-water. 

J ° [steam which condenses in the gasometer. [ 


Water----water. 

[steam which condenses in the gasometer.] 


Nitrous oxide is a colorless gas with a faint and agreeable 
odor, and a sweet taste. It supports the combustion of a taper, 
or a piece of phosphorus, with almost as much energy as pure 
oxygen. It is, however, easily distinguished from oxygen by 
its solubility in cold water, which takes up about three fourths 
of its volume of this gas. It is absorbed by water in nearly 
equal volumes. ( 80 ) When a recently extinguished lamp with 
a red wick is introduced into it, the flame is instantly restored. 
Sulphur, when burning feebly, is extinguished, but when well 
ignited its flame is considerably enlarged. ( 81 ) When mixed 
with an equal volume of hydrogen, nitrous oxide may be ex¬ 
ploded, liberating its own volume of nitrogen. ( 82 ) 

By the pressure of 50 atmospheres, at 45°, nitrous oxide be¬ 
comes a clear liquid, and, at 150° below zero, it freezes into 
a white snow-like mass. By the evaporation of this snow, a 
cold is produced, far below that produced by the evaporation 
of solid carbonic acid in a vacuum (p. 100,) or lower than 174° 
below zero. Solid nitrous oxide placed in the hand, by its sud¬ 
den liquefaction and evaporation, produces intense cold, form¬ 
ing a blister on the hand like , a burn. A single drop of liquid 
nitrous oxide also produces a wound like a burn. Metals 
dipped in this liquid produce a hissing sound, like that pro¬ 
duced by plunging red-hot iron into water. Ignited charcoal 
swims on its surface and burns with a vivid light, while sul¬ 
phuric and nitric acids are immediately frozen by contact with 
it. Water freezes in contact with liquid nitrous oxide, but at 


erties of nitrous oxide. At what temperature does nitrous oxide become solid ? 
What degree of cold is obtained by the evaporation of solid nitrous oxide? 
What effect is produced by the evaporation of a small quantity of solid or 
liquid nitrous oxide upon the hand ? What is the action of liquid nitric oxide 
on metals ?—on ignited charcoal ?—on sulphuric and nitric acids ?—on water ? 












THE ELEMENTS AND THEIR COMBINATIONS. 


119 


the same time causes the evaporation of the nitrous oxide 
with a rapidity almost equal to explosion. 

Nitrous oxide gas is more than once and a half heavier than 
air (sp. gr. 1.525.) The most remarkable effect of this gas is 
its intoxicating effect on the animal system. When inhaled 
it produces a strong propensity to laughter, a rapid flow of 
ideas, and an unusual disposition to muscular exertion. This, 
state of excitement is not followed by depression as is the case 
where alcoholic stimulants are used. To some constitutions, 
however, this gas is injurious, producing when inhaled, gid¬ 
diness, headache, faintness, and other disagreeable symptoms. 
An animal confined in this gas soon dies from the prolonged 
effects of the intoxication. 

168. Nitric oxide , deutoxide of Nitrogen , is formed by 
adding dilute nitric acid to copper clippings or turnings. 

Nitric ( nitr0 o en .. Nitric oxide. 

acid 1 ^ 0X yo en • [passes ° ff as gas,] 

* ( 3 oxygen 

Copper-_-oxide of copper. 

[unites with nitric acid.] 

Nitric acid-—^nitrate of copper, soluble salt. 

[r eraains in solution.] 

Nitric oxide is a colorless gas. In contact with air, or 
oxygen gas, it produces deep red fumes of liyponitric acid 

(p- '•«•) o 

This property serves to distinguish it from all other gases, 
and is also a convenient test for free oxygen. Wherever oxygen 
is free or uncombined, it is at once detected on the addition of 
nitric oxide by the red fumes produced. 

Cold water absorbs about three fourths of its volume of nitric 
oxide, and acquires a sweetish taste. The strong affinity with 
which nitric oxide retains its own oxygen, and absorbs oxygen 
in a free state, renders its action unfavorable in most cases of 
combustion. Many bodies that will bum in nitrous oxide, which 
contains but one equivalent of oxygen will not burn in nitric 
oxide although this contains two equivalents of oxygen (N0 2 ). 
Burning sulphur and a lighted candle are instantly extin¬ 
guished by it, but phosphorus and charcoal, if in a state of 


What is the specific gravity of nitrous oxide ? What is its effect upon the sys¬ 
tem when inhaled ?—on an animal confined in the gas ? 

168. How isniti'ic oxide formed ? Explain the diagram. Mention some of 
the properties of nitric oxide. How is nitric oxide distinguished from all other 
gases ? In what way is nitric oxide a test for free oxygen ? What other 
properties of nitric oxide are mentioned ? What is its action on combustion 1 







120 


ELEMENTS OF CHEMISTRY. 


vivid combustion when introduced into this gas, burn with in¬ 
creased brilliancy. ( 84 ) It is somewhat heavier than air (sp. 
gr. 1-525). With an equal bulk of hydrogen it forms a mixture 
that burns rapidly with a greenish-white flame. It cannot be 
breathed, as it produces a strong spasm whenever the attempt 
is made to inhale it. 

Carbon. Oxygen. Symbol. 

Carbonic oxide, 6 8 CO. 

169. Carbonic oxide is prepared by mingling in a retort 
eight or ten parts of sulphuric acid with one part of dry, finely 
powdered, yellow prussiate of potash. By a gentle heat the 
salt is entirely decomposed, and the gas may be collected over 
water. It is a colorless, almost inodorous gas, burning with a 
beautiful blue flame, such as is often seen on a freshly fed 
coal fire. The carbonic acid (C0 2 ), produced in the lower 
part of the fire, is converted into carbonic oxide (CO) as it 
passes through the red-hot coals, which withdraw a portion of 
its oxygen. From the red-hot coals it passes at a high temper¬ 
ature into the air, from which it immediately takes an equiv¬ 
alent of oxygen, burning with its blue flame and being con¬ 
verted into carbonic acid. It does not support the combustion 
of a candle. 

Carbonic oxide, and carbonic acid, illustrate the fact, that 
bodies whose composition are very nearly alike, maybe entirely 
different in properties. While carbonic acid is heavier than 
air (sp. gr. 1*524), carbonic oxide is lighter (sp. gr. 0-973). 
Carbonic acid is rapidly absorbed by water, carbonic oxide 
is not absorbed by pure water, or even by lime water. Car¬ 
bonic acid does not burn, while carbonic oxide mixed with half 
its volume of oxygen explodes. It explodes also when mixed 
with nitric oxide. Carbonic oxide has no acid properties like 
carbonic acid. ( 85 ) It is much more poisonous than carbonic 
acid, producing a state of the system resembling apoplexy. ( 86 ) 
Small animals immersed in it die instantly. 

Carbon. Hydrogen. Symbol. 

Light caejburetted hydrogen, 6 2 CH 2 . 

Heavy carburetted hydrogen, 12 2 C 2 H 2 . 


Why is it less favorable to combustion than nitrous oxide which contains only 
half as much oxygen ? What bodies are extinguished by it ? What sub¬ 
stances burn with increased brilliancy in this gas ? What is the specific 
gravity of nitric oxide ? What is said of its mixture with hydrogen 1 Can 
nitric oxide be inhaled ? 

169. How is carbonic oxide prepared ? What are some of its properties? 
How is carbonic oxide formed in coal fires ? What is its effect on the flame 
of a candle ? In what respects do oarbonic oxide and carbonic acid differ. 



THE ELEMENTS AND THEIR COMBINATIONS. 


121 


170. Light carburetted hydrogen, fire damp, is found 
abundantly in coal mines, being disengaged from the fresh cut 
surface of the coal, and from remarkable apertures called 
“ blowers,” which emit for a great length of time a copious 
stream or jet of gas. It is also found abundantly in stagnant 
pools during the decomposition of dead vegetable matter. 
From these places it may be obtained by stirring the mud at 
the bottom, and collecting the gas, as it escapes, by an inverted 
jar or other receiver. In this state it contains ten or twenty 
per cent, of carbonic acid, and a small portion of nitrogen. 
The carbonic acid may be removed by agitating it with lime 
water. It may be obtained also from a mixture of crystallized 
acetate of soda lour parts, solid hydrate of potash four parts, 
and powdered quicklime, six parts. When this mixture is 
strongly heated in a flask or retort, the gas is disengaged in 
great abundance, and may be received over water. 

Light carburetted hydrogen is a colorless and nearly inodor¬ 
ous gas. It burns with a strong yellow flame, producing car¬ 
bonic acid and water. It is not poisonous, and may be respired 
to a great extent without injury. All the value of the coal 
mines where this gas abounds, would have been lost, were it 
as poisonous as most of the gases. These vast deposits would 
also have been worthless, were this gas as infiammable as 
many of the other inflammable gases. By one property alone, 
in which the former differs from the latter, is the miner able 
to descend with safety into the mines. The latter, when mixed 
with air, may be exploded by an ignited surface, as a red-hot 
iron, but the former mixed with air, cannot be thus exploded. 
On this principle a lamp has been constructed, by which the 
miner can descend into the coal mines without any fear of pro¬ 
ducing an explosion by its flame. This lamp was invented by 
Sir Humphrey Davy, and called “ the safety lamp .” Its con¬ 
struction will be described in the section on combustion and 
flame, as it depends on certain laws or properties of flame not 
yet explained. One volume of light carburetted hydrogen ex¬ 
plodes when mixed with two of oxygen. One volume with ten 
of common air forms an explosive mixture. It detonates feebly 
when mixed with five or six times its volume of air. This 
small proportion, which is necessary to form an explosive mix¬ 
ture with air, accounts for the frequent and terrible accidents 
which occur in coal mines. 

170. Write the composition and symbols of light and heavy carburetted hy¬ 
drogen. Where is light carburetted hydrogen found ? How may this gas be 
prepared 1 Mention some of its properties. In what proportions does light 
carburetted hydrogen form an explosive mixture with oxygen ?—with com¬ 
mon air 1 



122 


ELEMENTS OF CHEMISTRY. 


COMBUSTION AND FLAME. 

171. Nature and came of combustion. Three conditions 
are necessary in all cases of combustion : a supporter of com¬ 
bustion, a combustible body, and the requisite temperature, 
which is generally above the ordinary temperature. ( 87 ) Under 
these circumstances, combustion always takes place. In the 
composition of gunpowder, oxygen (the supporter of combus¬ 
tion) is present in the saltpetre,* and carbon and sulphur (the 
combustibles) are also present. A red-hot iron produces the 
requisite temperature in a portion of the powder, and the great 
volume of the flame, thus produced, elevates the temperature 
of all that it reaches, so that the whole mass explodes. In its 
ordinary state, gunpowder needs but one of the above men¬ 
tioned conditions for its explosion—the requisite temperature* 
In its own composition it contains the combustible and the sup¬ 
porter of combustion. It will, therefore, explode in any situ¬ 
ation where the requisite degree of heat can be in any way 
conveyed to it. In blasting rocks this temperature is produced 
by a small train of powder connected with the mass within the 
rock. For the same reason, if a gun-barrel be filled with pow¬ 
der somewhat moistened, to diminish the rapidity of its com¬ 
bustion, and this moistened powder be set on fire at the end 
of the barrel, it will continue to burn, although the end of the 
barrel be stopped, as with a thick covering of cloth, or be 
plunged under water. In the latter case the gas, pouring 
forth in volumes from the powder burning within the guri- 
barrel, may be collected in jars above the water. The same 
experiment may be performed with a fusee. If the fusee be 
lighted at one end, it cannot be put out by placing weights 
upon it, nor by causing a length of it to pass under water. 
The fusee burns until it is entirely consumed, or the burning 
part is cut off from the rest. But apart from each other, the 
elements which form gunpowder will not explode, or even 
burn. Saltpetre may be melted and heated red hot by itself, 
without either explosion or combustion. Charcoal and sul- 

* This may be seen by referring to saltpetre (208) the symbol of which 
shows a large amount of oxygen in its composition. 


171. What three conditions are necessary in all cases of combustion ? How 
is this illustrated in the composition of gunpowder ? Which one of the three 
conditions is wanting in the ordinary state of gunpowder ? How is the tem¬ 
perature required for the explosion of powder produced in blasting rocks ?—in 
burning powder underwater 1 Will the elements of gunpowder explode apart 
from each other 1 How may this be proved by experiment 1 In what man- 



THE ELEMENTS AND THEIR COMBINATIONS. 123 

phur may also in like manner be heated by themselves* with¬ 
out combustion ; hut, if the heated charcoal or sulphur be 
poured into red-hot saltpetre, a vivid combustion will instantly 
take place with almost explosive energy. ( 88 ) In this manner 
the ancients formed what was called the Greek fire. Sul¬ 
phur, resin, alcohol, camphor, and other combustibles, were 
melted with saltpetre, and in this melted mass cords were 
dipped and rolled up into balls. These balls being set on 
lire and thrown into the enemy’s camp, could not be extin¬ 
guished, for they contained in their own composition all the 
elements of combustion, and the energy with which they 
burned maintained constantly a very high temperature. When 
Constantinople was attacked in the reign of Leo, many of the 
ships of the besiegers were destroyed by this composition. ( 89 ) 
On the other hand, the absence or "deficiency of either the 
supporter of combustion, the combustible body, or the requisite 
temperature, prevents combustion. Too much fuel put on a 
fire smothers it, because the air, the supporter of combustion, 
is shut out out from the fire, or cannot act on the fire in suffi¬ 
cient quantity. If the fire is not replenished, it goes out, be¬ 
cause the combustible has all been consumed, that is, it has 
all united with the oxygen of the air. In this case, the sup¬ 
porter of combustion may be obtained in inexhaustible quantity 
from the air, and therefore as long as the fuel is supplied, and 
the air allowed free access, the combustion will be maintained. 
When blown by the bellows, the fire burns with greater energy, 
because the oxygen of the air is brought more perfectly into con¬ 
tact with the fuel. For this reason, in wind furnaces, the fire 
is rendered intensely hot by the blast of air, the effect of which 
is more in proportion to its velocity than its quantity. The 
blast of air is increased in two ways, by increasing the draught 
of the chimney, and by bellows and blowing machines. The 
breathing of a multitude of persons in a building soon exhausts 
the air, to a great degree, of its oxygen. In such assemblies, 
therefore, the lights have sometimes been observed to burn very 
dim, owing to the great deficiency of oxygen, and the produc¬ 
tion of carbonic acid. 

* Out of contact with the oxygen of the air, or, to a moderate degree, in the 
air. 


ner was Greek fire formed ? Why could not this fire be extinguished ? Why 
does the addition of too much fuel smother a fire ? Why does the fire go out 
when not replenished 1 When blown by a bellows why does a fire burn with 
greater energy 1 Is the effect of a blast of air more in proportion to its quantity 
or its velocity ? Why do lights sometimes burn dim in a crowded assembly ? 



124 


ELEMENTS OF CHEMISTRY. 


172. Phenomena and cause of flame. When the temper¬ 
ature of inflammable gases is raised very high, and in contact 
with the air, they burst into a flame. If previously mixed 
with a due proportion of oxygen, or of atmospheric air, they 
explode. In the first case, the supporter of combustion (oxygen 
of the air,) was entirely on the surface of the flame ( 90 ) ; in 
the second case, it was mixed in with the gas, and the com¬ 
bustion was therefore instantaneous and throughout its mass. 
Ordinary flame is produced by the contact of air with the sur¬ 
face of the ignited gas ; hence,, on the surface only does the 
combustion of ordinary flame take place. Flame is therefore 

hollow. ( 91 ) It presents a cone of gas (Fig. 58). This 
Fig. 58. C one consists of a dark central part, A, surrounded 
by a highly luminous cone or envelop, B, and on the 

. C outside a second cone, C, feebly illuminated. The 

// \\' B flame may be considered as made up of two gases, 

A4 .a carbon and hydrogen, of which hydrogen possesses 

far the greater attraction for oxygen. Therefore, at 
pH a little distance within the surface of the flame, the 
' * hydrogen takes all the oxygen, and the carbon, though 

intensely ignited by the flame of the hydrogen, is not burnt. 
This is the origin of the light, for the solid particles of carbon, 
when thus intensely ignited without the possibility of being 
burnt, give out great light. ( 92 ) This unburnt carbon of the 
inner flame collects at once on any solid substance placed over 
the flame. The mode of deposition may be best seen by draw¬ 
ing a piece of wire-gauze over the flame so as to reach to 
B. ( 93 ) In the exterior cone, C, these particles undergo com¬ 
bustion, and, in this state, produce less light than while in¬ 
tensely ignited in the inner flame. 

173. That the light given out by flame is owing to the 
solid particles of ignited carbon, is evident from the fact that 
flames which contain the least carbon and the greatest 
amount of hydrogen give little light. Such is the flame of a 
spirit lamp. This, and the flame of pure hydrogen, give great 
heat but little light. Their great heat arises from the fact 
that little or none is expended in igniting carbon, and this ab- 


172. Under what circumstances do gases burst into a flame ? In what way- 
are gases exploded ? When are gases said to burn with a flame 1 —with ex¬ 
plosion ? Explain Fig. 58. Of what two gases is flame composed ? Which 
possesses the greater attraction for oxygen ? In what state is the carbon 
withm the flame 1 What then is the origin of the light of flame ? How may 
t*he unburnt carbon be shown by experiment ? What is said of the carbon in 
the exterior cone, C V 

173. What facts show that the light given out by flame is owing to the igni¬ 
tion of solid particles of carbon ? What effect is produced by throwing solid 




THE 'ELEMENTS AND THEIR COMBINATIONS. 125 

sence of carbon accounts also for the little light which they 
give. If any solid matter, as magnesia or lime, be thrown 
into the flame of hydrogen, this flame instantly becomes more 
luminous. If a platinum wire be held in the same flame, it 
will become ignited and give out an intense white light. If, 
on the other hand, the solid carbon is burnt in such a manner 
as not to be intensely ignited, the flame gives out but little 
light. Thus if coal gas (p. 128.) be mingled with an equal bulk 
of air, the carbon burns more readily and becomes so feebly 
ignited that the gas loses half its illuminating power. 

174. When flames are cooled they are at the same time ex¬ 
tinguished ; hence when a piece of wire-gauze is 

held in a flame, the smoke will pass through, Fig. 59. 
but become too much cooled to ignite above. 

When this smoke is heated by a second flame 
brought near to it, it takes fire and burns above 
the wire-gauze.( 94 ) Upon this principle the 
safety lamp, (Fig. 59.) is constructed. C is a 
cylinder of wire-gauze, which terminates in a 
metallic ring, It. This ring screws on to the 
lamp, L. E is a tube extending nearly to the 
bottom of the lamp, that the end of this tube 
may be always covered with the oil of the lamp, 
and communication between the air within and 
without the lamp, in this way, prevented. 

Through this tube the lamp is filled with oil. 

At F, is seen the flame and a bent wire for trim¬ 
ming the wick. 

When this lamp is carried into an atmos¬ 
phere charged with explosive gas, a blue flame is observed 
within the gauze cylinder from the combustion of the gas, and 
the flame in the centre of the lamp may be extinguished. To 
provide against such cases, a coil of platinum wire is attached 
to the wick, which relights the lamp, when the miner speedily 
returns to better air. This coil remains ignited by the prop¬ 
erty which platinum wire possesses of decomposing oils, alco¬ 
hol, &c., as will be explained hereafter. 

175. The blowpipe is designed to concentrate the heat of 
flame on a small object by a current of air blown through the 



matter in a state of minute division into a hydrogen or alcohol flame? What 
effect has a hydrogen flame on a platinum wire ? Is the light of flame increased 
or diminished by burning more effectually .the carbon ? How is this shown in 
the case of coal gas ? 

174. What is the effect when the temperature of flame is lowered ? By what 
experiment is this illustrated? Explain Fig. 59. 

















126 


ELEMENTS OF CHEMISTRY. 


flame. The blowpipe flame, (Fig. 60.) is ignited nearly 
throughout , but different parts of the flame differ in their de¬ 
gree of ignition, and the extent to which the gas of the flame 
is consumed. Thus at the centre of the flame, or A, the gas 
is perfectly consumed, as this is in the direct line of the air 
blown from the mouth. On the outside, or 
Fig. 60 . surface of the flame, the gas is also con¬ 
sumed, but between the outside and the 
centre of the flame, there is a thin stratum 
which is unconsumed, and which accumu¬ 
lates towards the extremity, in the space 
from B to C. This space, consequently, has 
a white color, and differs in chemical properties from the rest 
of the flame. At the point B, the gases are so hot that they 
have a powerful attraction for oxygen, which they consequent¬ 
ly absorb from most substances that are placed in this part of 
the flame. This part is therefore called the reducing flame, 
as it reduces bodies from their oxides ; for example, when the 
oxide of lead is exposed to this part of the flame, pure lead is 
reduced , or obtained. 

The outer portion of this flame is drawn out by the blast of 
air into a long cone, BC, the termination of which is of a blue 
color. In this part of the flame the gases are not so hot, and 
do not surround the object at the termination of the cone, at 
C. Hence, when a body is placed in this part of the flame, its 
oxygen is not taken away from it, but usually it acquires more 
from the atmosphere. This portion of the flame is therefore 
called the oxidizing flame. The hottest part of the blowpipe 
flame is a point between the outer and the 
Fig. 61. inner flame.( 96 ) 

, 176. The oxy-hydrogen blowpipe is an instru- 

ji ment which produces the most intense heat by 

Vjl a flame of hydrogen and oxygen. These gases 
are k e pt i n separate reservoirs, but are made to 
jf IT unite by a compound gas jet. In Fig. 61. c and 
wk- e are india-rubber tubes, connecting one with the 
JJ 'X hydrogen and the other with the oxygen gasome- 
// \\ ter. These are fastened to brass tubes provided 

with stop-cocks, b and d. These tubes unite in 
the compound jet, a. The construction of this jet is repre- 



175. What is the object of the blowpipe ? Explain Fig. 60. What portion 
of the blowpipe flame is called the reducing flame ? Why is it so called ? 
What is meant by the oxidizing flame of the blowpipe ? Why is this so called ? 

176. What is said of the oxy-hydrogen blowpipe ? Explain Figure 61.-— 





THE ELEMENTS AND THEIR COMBINATIONS. 


127 


sented in Fig. 62. The central dot is the aperture at which 
the oxygen issues. To this aperture it is brought in the tube 
represented by the dotted line. Outside this tube, and between 
it and the tube marked a , the hydrogen passes and issues be¬ 
tween the two tubes, and around the jet of oxygen. 

The gases therefore do not mingle until they leave the Flg * 62 * 
tubes and at the flame itself. There is, therefore, no ^ 
danger of explosion, while the hydrogen, being supplied M 
within by the oxygen from the gasometer, and without M 
by the oxygen of the atmosphere, burns in a flame of 
great intensity. The quantity of the two gases can be easily 
regulated by the stop-cocks, b and d (Fig. 61.) 

By the oxy-hydrogen blowpipe, substances perfectly infusi¬ 
ble in a common furnace melt at once. Platinum melts like 
wax, and is even volatilized. By bringing the flame to bear 
on a cylinder of lime, a most intense light is produced. This 
is the principle of the Drummond light, as will be shown 
hereafter. 

177. Heavy carburetted hydrogen, olefiant gas. This gas 
has twice as much carbon as light carburetted hydrogen (p. 
120). It is prepared by mixing strong alcohol with five or six 
times its weight of sulphuric acid, in a capacious retort, and 
applying a gentle heat to the mixture. If too much heat is 
applied, the mixture foams up, and is apt to run out at the 
neck of the retort. Towards the latter part of the operation, 
carbonic and sulphurous acids are given off The operation, 
therefore, should be discontinued after the gas ceases to come 
over freely. 

C 4 carbon -Olefiant gas (C 4 H 4 or 2 C 2 H„.) 

Alcohol, { 6 hydrogen-^ * passes offa * ^ as * ] 

( 2 oxygen-—water (H 2 0 2 or 2 U 2 H 2 HO.) 

[disxilled with the olefiant gas.] 

Sulphuric acid-,-^sulphuric acid. 

[acts only by its presence, 12, p. 60.] 

Olefiant gas is colorless, tasteless, and inodorous. Water ab¬ 
sorbs one eighth of its volume by standing. It burns with a 
splendid white flame.( 96 ) ~Tt extinguishes a candle, for neither 


Explain Fig - . 62. Why do not the mixed gases in this blowpipe explode ? To 
what is the great intensity of this flame owing ? How may the proportion of 
either gas in the compound flame be regulated ? Mention some of the effects 
produced by the oxy-hydrogen blowpipe. 

177. How does the amount of carbon in olefiant gas compare with that in light 
carburetted hydrogen ? State the process for preparing olefiant gas, and explain 
the diagram. What are some of the properties of olefiant gas ? Why does 
this gas extinguish combustion? What is said of the specific gravity of this 
gas and light carburetted hydrogen ? With what proportion of oxygen does it 
form an explosive mixture ? What are the proportions for an explosive mix- 










128 


ELEMENTS OF CHEMISTRY. 


of its elements is a supporter of combustion. It is much 
heavier (sp. gr. 0-981) than light carburetted hydrogen (sp. gr. 
0-559), but both these gases are lighter than air. A mixture 
of one part of olefiant gas with three parts of oxygen, when 
inflarAed, explodes with a loud report. It also forms an ex¬ 
plosive mixture with ten parts of common air.( 97 ) Chlorine 
acts upon olefiant gas in a remarkable manner. When these 
two gases are mixed, even in the dark, they combine in equal 
measure, and give rise to a heavy oily liquid of sweetish taste 
and ethereal odor, to which the name of chloride of hydrogen, 
or Dutch liquid > is given. It is from the formation of this 
oily substance by the mixture of two gases, that the term 
olefiant (oil making), is derived. When mixed with twice its 
volume of chlorine in a tall jar, and lighted on the top, it burns 
with a splendid red flame, leaving a dense deposit of carbon on 
the interior of the jar. In this experiment, the chlorine and 
hydrogen unite, forming hydrochloric aeid, and the carbon is 
set free. Olefiant gas is decomposed by being passed through 
a tube heated to bright redness. If the temperature is very 
high, a deposit of charcoal is produced, and light carburetted 
hydrogen, or even free hydrogen, given off. 

Olefiant gas is given off naturally in great abundance at 
several places. A natural supply of this gas, mixed with light 
•carburetted hydrogen, is used to light the city of Fredonia, 
N. Y. It also occurs at Salina, and at Niagara, at the edge 
of the river above the rapids. At some of the salt works at 
Kenawha, Ya., the kettles for evaporating the salt are heated 
by conducting the burning gas under them. Vast quantities 
of this gas are given off from the Artesian borings in those 
regions. ( 08 ) 

The gas used in lighting cities , owes its illuminating power 
to the amount of olefiant gas which it contains. Explosions 
often occur from the gas becoming mingled with the air of the 
house, by escaping from the jet. Only one tenth part of the 
gas is required to render the air explosive. The gas for 
lighting cities is usually made from coal. Were it not for its 
greater cost, oil gas would be much preferred to that made 
from coal, for it possesses far higher illuminating power. It is 
made by dropping oil into a red-hot iron retort, filled with 


ture with common air ? What is said of the action of chlorine on olefiant gas ? 
Whence is the name olefiant derived ? How may this gas be decomposed ? 
Which of the components is deposited ? Which is given off? Mention some 
of the places where olefiant gas occurs naturally and in great abundance. To 
what does the gas used in lighting cities owe its illuminating-power ? Of wliat 
is this gas usually made ? Why is not oil gas used ? From what other source 
may gas be produced ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


129 


coke, which exposes a large ignited surface to the oil. Illu¬ 
minating gas may also be produced abundantly from cotton 
seed, and of a finer quality than that from either coal or oil, 
a process first discovered and described by Professor Olmsted.^ 
178. Coal gas. In Fig. 63, some of the principal arrange¬ 
ments used in the gas works are represented, a, a , a, are 
three retorts which project out from the brick work, b, to a 
distance sufficient to allow the pipes, c, c, c, to pass outside of 
the furnace. These pipes pass from the retort into a large pipe 
called the hydraulic main. They enter through a stratum 


Fig. 63. 



of condensed tar and water, which covers the bottom of the 
hydraulic main, and terminate in thimbles, f f f, which are 
supported above the pipes by bolts, g, g, g. A small pipe, h, 
carries off the excess of tar and water, which condenses in the 
hydraulic main. This pipe descends into the short cylinder i, 
into which, consequently, the excess of tar and water is emp¬ 
tied. When the cylinder is filled to the level of the pipe, j, 
the tar and water flow off through this pipe into the tar well , 
which is not represented in the figure. 

* American Journal of Science, Vols. VIII. and IX. 


178. Explain Fig 63. Which of the impurities of the gas are first removed ? 
How is this effected? What is the object of the thimbles/,/,/? What 

6* 






























































130 


ELEMENTS OF CHEMISTRY. 


The gas rises through the pipes, c, c, c, passing through the 
thimbles, / f, f beneath the stratum of tar and water, and 
bubbles up into the space above. From the hydraulic main it 
passes through the pipe, k, and descends into the large cylin¬ 
der, l. In this cylinder it meets with a very small stream of 
water, m, which is brought through the pipe, m, m, from a 
reservoir of water, at an elevation of fifteen or twenty feet 
above the cylinder, l, and consequently issues with great force. 
Striking on a projection within the cylinder, this stream is 
dissipated in spray immediately in front of the stream of gas. 
The object of this arrangement will be explained below. The 
water from this spray collects on the lower part of the cylin¬ 
der, and passes off through the pipe, n. The gas is carried off 
in the pipe, o. 

The retorts, a , a , a, are opened, and coal ( 9 ^) thrown in 
rapidly. To this, in some cases, a single shovel-full of rosin 
is added. The doors of the retorts are then closed and screwed 
up, so as to be air-tight. (") The gas is driven off by the heat 
of the fire, beneath the retorts. In this state, it is so impure, 
as to be unfit for the purposes of illumination The first ob¬ 
ject, therefore, is to remove these impurities. By a diminu¬ 
tion of temperature, as the gas passes through the pipes, c, c, c, 
and into the hydraulic main, most of the coal tar and watery 
vapor is condensed. The remainder is afterwards condensed 
in the pipes and cylinders, through which the gas passes. The 
object of the thimbles,/, ff is to break the connection between 
the pipes, c, c, c, or between the retorts, a, a, a. By this ar¬ 
rangement, when one of these retorts is opened, the gas from 
the other retorts, and the hydraulic main, cannot descend 
through the pipe, c, and escape into the air. 

When the tar and watery vapor are condensed, the next ob¬ 
ject is to absorb the ammonia, which is another impurity of 
the gas. This is done by the small jet of water in the cylin¬ 
der, l . The very fine spray into which this jet is dissipated, 

brings the water and the gas into 
■Fig 64 ’ perfect contact, and produces a 

complete absorption of the ammo¬ 
nia. % 

The remaining impurities of the 
gas are, chiefly, sulphuretted hy¬ 
drogen and carbonic acid. To re¬ 
move these, a box, a, (Fig. 64.), 



impurity is removed from the gas in cylinder l ? How is this accomplished ? 
Explain Fig. 64.—Fig. 65. How is the purity of the gas after passing through 




THE ELEMENTS AND THEIR COMBINATIONS. 


131 


containing slaked lime is employed. The interior of this 
box is seen in Fig. 65. The gas en¬ 
ters at b , beneath a frame work Fig. 65 . 

of wire-gauze. The slaked lime 
is placed upon this wire-gauze, 
through which the gas passes and 
leaves the box at c. By passing 
through the apertures of the wire- 
gauze, the gas is brought into per¬ 
fect contact with the lime. It is necessary that the gas 
should pass through three of these boxes, before it is suffi¬ 
ciently pure for use. The degree of its purity, is determined 
by test-papers , which are prepared with acetate of lead. One 
of these test-papers is held over the stop-cock, d , (Fig. 64,) 
which is then opened, and a stream of gas let out on the 
paper. If sulphuretted hydrogen be present, it immediately 
blackens the paper, by the formation of sulphuret of lead. This 
effect is instantaneously produced bytlie gas from the first box, 
after some time by that from the second, and not at all by that 
from the third. 

The gas, being purified, passes from the lime-box through 
the pipe, c , (Fig. 65,) to the gasometer. This is a large reser¬ 
voir of peculiar construction, designed to receive all the gas 
which is made, both during the day and night,, and to distrib¬ 
ute this by the pressure of its weight through the pipes of the 
city. The general principle of its construction may be illus¬ 
trated in the following way : 

If a receiver, like one of those represented in Fig. 33, 
page 63, be filled with water, it will sink beneath the surface, 
and may there be inverted. It now stands entirely beneath 
the surface of the water, and rests upon the bottom of the pneu¬ 
matic trough. Underneath the receiver introduce a benftube, 
and force a small portion of air within. This will rise, and, 
if in sufficient quantity, it will buoy up the receiver so that it 
will float in the water. 

The gasometer may be considered as an immense receiver. 
A pipe from the gas-works introduces gas from beneath, and 
the cylinder is buoyed up from the water, by which it is sur¬ 
rounded, and with which it is at first filled. This cylinder is 
surrounded by another which holds the water, and between the 
outer and the inner cylinder, wheels are placed by which the 



the lime boxes determined ? To what does the gas pass from these boxes ? 
Explain the principle of the gasometerits construction. For what purpose 
is water kept in the iron trough beneath the fire ? How does the vapor of 





132 


ELEMENTS OF CHEMISTRY. 


rise and fall of the inner cylinder is effected with less friction. 
A mast also runs up from the centre, which serves to steady 
the inner cylinder against winds, and other causes of agitation. 
From the gasometer the gas passes off in a large pipe to the 
city. 

In the general description given above, several facts have 
been omitted, Some of these may now be mentioned ; espe¬ 
cially those which illustrate chemical principles. 

In Fig. 63, p. 130, is seen an iron trough p, which is kept 
constantly full of water. The vapor of this water rising through 
the fire, is decomposed, its hydrogen is burnt, and thus affords 
a volume of flame which plays about the retorts, and greatly 
increases the effect of the fire. The oxygen of the water also 
increases the intensity of the combustion. Water is used with 
the same kind of coal, and for a similar purpose, in the black¬ 
smith’s forge. 

The fuel employed is coke. This is made in the retorts, 
and is what remains from the coal after the gas is driven off. 
When drawn out of the retorts, the coke is in an ignited state. 
It is therefore received into iron wagons, and drawn without 
the building, where it is extinguished with water. By this pro¬ 
cess it absorbs a great deal of water, and this, as well as that 
which rises in vapor from the iron trough beneath the fire, is 
an important part of the fuel. In this way, the coke produced 
is usually found more than sufficient for the supply of the fire. 
(i°°) excess i s soi^ and i s> therefore, one of the items of 

profit in gas works. The coal-tar is also sold, and has of late 
come to be in demand as an article of fuel in glass works, being 
used instead of rosin, which has been hitherto employed, to in¬ 
crease the intensity of their fires. The lime from the boxes 
(Fig. 65,) being charged with carbonic acid and sulphuretted 
hydrogen, is valuable for manure. The ammoniacal liquor 
produced in cylinder l (Fig. 63,) is of great value in agricul¬ 
ture, and forms the chief source of the ammonia of commerce. 

Phosphorus. Hydrogen. Symbol. 
Phosphuretted hydrogen, 31 3 PH 3 . 

179. Phosphuretted hydrogen is formed, when the phos- 
phuret of calcium is acted on by water. For this purpose, fill 
a small retort with water, entirely full , and through the top 


water increase the energy of the fire ? What is the fuel employed in gas¬ 
works ? How is this obtained ? What is done with the excess of coke?— 
the coal-tar ?—refuse lime ?—ammoniacal liquor ? 

179. Write the composition and symbol of phosphuretted hydrogen State 




THE ELEMENTS AND THEIR COMBINATIONS. 


133 


or neck of the retort, drop a few pieces of the phosphuret of 
calcium. These will sink to the bottom of the retort, and a 
stream of gas will rise to the top and inflame on coming in 
contact with the air. The neck of the retort is now closed 
with the stopper, and the gas, gradually increasing in amount, 
at length fills the retort and excludes the water, and finally 
issues from the retort, and rises above the water in bubbles, 
that inflame on coming in contact with the air. The gas may 
be collected in jars, by the displacement of water. 

Phosphuretted hydrogen may also be made by filling a small 
retort with water, containing quicklime recently slaked. Into 
the retort thus prepared, drop a few pieces of phosphorus, and 
apply a gentle heat. The gas will gradually accumulate, as 
in the last process, and drive out the lime-water : it will then 
issue from the retort in bubbles, which are spontaneously in¬ 
flammable. 


Phosphorus, - * • • Phosphuretted Hydrogen. 

Water j hydrogen [passes off in gas.] 


( oxygen 
Phosphorus,- 

Lime- 


-hypophosphorus acid. 

[unites with lime.] 

-hypophosphite of lime, sol. salt. 

[remains in solution.] 


If a small jar of phosphuretted hydrogen be collected, and 
inverted in contact with the air, it will burn with a beautiful 
white flame. When kept over water for some time, it loses 
this property, without undergoing any appreciable change. 
Charcoal, and other porous absorbents, also destroy the spon¬ 
taneous inflammability of this gas, and the same effect is pro¬ 
duced by a minute quantity of several combustible bodies, as 
the vapor of potassium, ether, or essential oil. It detonates 
with oxygen, combining with half its volume of this gas. 
Only one bubble of either of these gases should be let up into a 
jar of the other at a time, as a much larger quantity would 
produce a violent explosion. Phosphuretted hydrogen also ex¬ 
plodes with chlorine, giving a brilliant greenish-white light. 
With nitrous oxide gas, it detonates by the electric spark. It 
is somewhat heavier than air (sp. gr. 124). Its odor is very 
disagreeable, resembling the smell of fish in a state of decom¬ 
position, which is owing to the formation of this gas. 

the method of preparing this gas ;—the second method. Explain the diagram. 
What is the most remarkable property of phosphuretted hydrogen 7 How may 
its spontaneous inflammability be destroyed 7 In what proportions does it 
detonate with oxygen 7 With what other gas does phosphuretted hydrogen 
explode7 How may it be exploded with nitrous oxide gas? What other 
properties of phosphuretted hydrogen are mentioned? 







134 


ELEMENTS OF CHEMISTKY. 


Phospliuretted hydrogen exists in three forms, which have nearly 
the same composition,—the solid, the liquicj, and the gaseous forms. If 
the spontaneously inflammable*gas, which is a mixture of two, or of all 
the forms, is passed through a tube cooled by a freezing mixture, on issu¬ 
ing from the tube, the gas has lost its spontaneous inflammability on 
contact of the air, and a colorless liquid is deposited in the tube, with 
some ice from the condensed and frozen watery vapor. This liquid, by 
inclining the tube, can be collected in one end, and there sealed by a 
blowpipe flame. The addition of a drop of this liquid to any of the com¬ 
bustible gases will render them spontaneously inflammable. Thus if a 
drop be introduced into a bell-glass of hydrogen, it is converted into va¬ 
por, and a gaseous mixture is formed, which takes fire at once on contact 
of the air. 

This liquid can be preserved only in the dark. In the light it is soon 
decomposed into phosphuretted hydrogen gas, and into a solid body of 
an orange yellow color. This solid contains yet more phosphorus than 
the liquid, which also contains more than the gas. It is also obtained on 
the sides of the jars in which the spontaneously inflammable gas has been 
kept for some time over mercury. 

Many bodies decompose the vapor of the liquid phosphuretted hydro¬ 
gen, which is contained in the spontaneously inflammable gas, and thus 
deprive it of this property of taking fire spontaneously on contact of air. 
When this gas is prepared from phosphuret of calcium with hydro¬ 
chloric acid instead of water, this decomposition takes place, and the re¬ 
sulting gas is not spontaneously inflammable. On the other hand there 
are many bodies which decompose a small 'portion of the gas, removing 
a portion of the hydrogen, and thus causing it to pass to the state of 
liquid phosphuretted hydrogen, and the whole to the spontaneously in¬ 
flammable state. 

Phosphuretted hydrogen decomposes some metallic solutions, 
as those of copper and mercury, and forms metallic phosphides. 
When pure, it is entirely absorbed by sulphate of copper and 
by chloride of lime. 

180. The following table exhibits the composition, symbols, 
and combining numbers of the neutral compounds of the non- 
metallic elements. 




NEUTRAL COMPOUNDS. 


1. OXYGEN COMPOUNDS. 

Nitrogen } Nitrous oxide 

Oxygen ) Nitric oxide 


NO. 

14+8=22. 

N0 2 . 

14+16=30. 


180. Write the composition, symbols, and combining numbers of the neutral 
oxygen compounds of the non-metaUic elements ; - the hydrogen compounds. 





THE ELEMENTS AND THEIR COMBINATIONS 


135 


Carbon 

Oxygen 


| Carbonic oxide 


CO 

6+8=14. 


Carbon 

Hydrogen 

Phosphorus 

Hydrogen 


2. HYDROGEN COMPOUNDS. 

Light carburetted hydrogen 
Heavy carburetted hydrogen 


• Phosphuretted hydrogen 


CHo. 

6 + 2 = 8 . 

C H 3 . 
12+2=14. 

ph 3 . 

31+3=34. 


>■ 


ALKALINE COMPOUND OF NON-METALLIC 
ELEMENTS. 


Nitrogen. Hydrogen. Symbol. 

Ammonia, 14 3 NH 3 . 

181. Ammonia is the only alkaline compound of the non- 
metallic elements. It is prepared from equal parts of muriate 
of ammonia, or sal ammoniac, and freshly slaked dry lime. 
These are mingled and heated in a glass or iron vessel ; in the 
latter, when the quantity of the mixture is considerable. It 
may be collected by inverting a jar over the end of the tube 
from which the gas issues. Being lighter than air, it will dis¬ 
place it ( 101 ), and fill the inverted jar. It may also be collect¬ 
ed over mercury. 


Sal am¬ 
moniac, 

Lime— 


ammonia- 


hydrochlo- j hydrogen-^water. 


■Ammonia. 

[passes off as gas.] 


ric 


acid ( chlorine 


oxygen 
calcium- 


[passes off in vapor.] 

-chloride of calcium. 

[remains in the retort.] 


Ammonia is a colorless gas, with a pungent, exciting, and 
enlivening odor. By its caustic properties it acts powerfully 


181. What is the only alkaline compound of the non-metallic elements? 
Write the composition and symbol of ammonia. State the process for prepar¬ 
ing ammonia. Explain the diagram. Mention some of the properties of am¬ 
monia. In what way may ammoniacal gas be separated into its elements . At 
what temperature and pressure does it become a liquid ? To what extent is 










136 


ELEMENTS OF CHEMISTRY. 


on the eyes and nose. It cannot be breathed in its pure form ; 
but, when diluted with air, it may be taken into the lungs 
with safety. It does not take fire with the flame of a candle, 
nor does it support combustion. The flame is, however, con¬ 
siderably enlarged, and is tinged with a pale yellow color when 
immersed in the gas A small jet of ammonia burns in oxy¬ 
gen, and, in about equal volumes,* it forms with oxygen an 
explosive mixture. With iodine, ammonia forms an explosive 
compound, called the iodide of nitrogen. It is prepared by 
dropping a few grains of iodine into a phial of dry ammoniacal 
gas. The iodine is agitated in contact with the gas, and it 
becomes gradually changed to a viscid brown substance, which 
is a compound of iodine and the nitrogen of the ammonia. 
This substance is exploded by the warmth of the hand with 
great violence. 

Like the compounds of carbon and hydrogen, this gas is 
lighter than air. The specific gravities of these three gases 
are, 0-559 (light carburetted hydrogen), O’589 (ammonia), 
0-981 (olefiant gas). 

Ammoniacal. gas may be separated into its elements by 
passing electrical sparks through it for a considerable time. 
Under a pressure of 6-J- atmospheres, at 50°, it becomes a 
transparent, colorless liquid. This gas is absorbed by charcoal 
to the extent of 90 times its volume.( 102 ) 

Water, at the ordinary temperature dissolves about 7000 
times its volume of ammoniacal gas, although the solubility 
of the latter is greatly affected by its temperature. When 
ammonia is prepared in winter and the bottle in which it is 
contained is afterwards opened in a warm day of summer, the 
gas escapes with effervescence, and such force as to throw the 
liquid out of the bottle in a fountain or jet sometimes ten or 
fifteen feet high. To obtain a highly saturated solution the 
bottle in which the ammonia is absorbed is sometimes sur¬ 
rounded with ice.( 103 ) By heat, the greater part of the gas can 
be again expelled. The concentrated solution is a clear, color¬ 
less liquid. Its density is nearly that of water (sp. gr. 0875). 
It possesses the odor, taste, and other properties of the gas 
itself. It is not corrosive, but tastes highly alkaline. When 
cooled slowly to—40°, it crystallizes in long needles of a silky 

* Four of ammonia to three of oxygen. 


ammonia absorbed by charcoal ?—by water ? Mention some of the properties 
of this solution. In what three ways is free ammonia detected ? How may it 
be detected in its salts? What are some of the sources of ammonia ? In what 
way may the escape of ammonia from manure heaps be prevented 1 What is 



THE ELEMENTS AND THEIR COMBINATIONS. 


137 


lustre. Ou account of its great volatility, it must be kept in 
well stopped bottles. Alcohol also dissolves ammonia in large 
quantity. 

Ammonia in a free state , is known in three ways, by its 
odor, by its action on vegetable infusions, or reddened litmus 
paper ( 104 ), and especially by the white cloud formed on bring¬ 
ing to it a rod moistened with hydrochloric acid.( 105 ) In any 
of its salts it can also be detected by being heated with hydrate 
of lime, or solution of caustic potash or soda, by which these 
salts are decomposed, and ammonia evolved in a free state.( 106 ) 

Ammonia is given off in vast quantities in the decomposition 
of animal and vegetable substances. Its salts form excellent 
manure for soils. They are the principal ingredient in many 
kinds of manure, and, therefore, the escape of ammonia from 
manure heaps, should be prevented by sprinkling them from 
time to time with diluted sulphuric acid, or by strewing gyp¬ 
sum over them. These substances form with the ammonia, 
sulphate of ammonia, a salt which does not volatilize at com¬ 
mon temperatures, and which is beneficial to the soil, both 
from its ammonia and its sulphuric acid. Moist, absorbent 
earth answers the same purpose to some extent. 

Ammonia has been found in the roots of beet, in the stem 
of the maple-tree, and of the palm, and in all blossoms and 
fruit in an unripe state. It exists also combined with acids, 
in some of the saline products of volcanoes, and, in very small 
quantities it may be detected in sea-water. It is found in 
small quantity in the air, especially in towns where bituminous 
coal is burned to a great extent, and in large cities. Small 
stellated crystals of the sulphate of ammonia are sometimes ob¬ 
served on the windows of these cities. 

The composition, symbol, and combining number of this al¬ 
kaline compound are 



Ammonia NH 3 . 

14+3 


Amidogen. On heating potassium (203) in ammoniacal gas (NTE 3 ), one 
third of the hydrogen is set free, and the remainder NH 2 combines with 
the potassium, forming a compound K, NH 2 , which is called the ami- 
d de of potassium, and the body NH 2 is called amidogen. By some it is 
thought that ammonia (NH 3 ) is a compound of amidogen and hydro¬ 
gen ;—that, as oxygen unites with hydrogen to form water, so amidogen 
unites with hydrogen to form ammonia. 


the action of sulphuric acid or gypsum in this case? Where is ammonia 
found in plants combined with acids? Write the composition, symbol, and 
combining number of ammonia. 



138 


ELEMENTS OF CHEMISTRY. 


ENDOSMOSE, EXOSMOSE, DIFFUSION OF GASES. 

182. A glass tube, a , (Fig 66.) is closed at the bottom by 
(a piece of bladder, india-rubber, &c.) and 
filled with a liquid to b. It is then placed 
in the vessel, b d, which contains a liquid 
different from that which the tube contains. 
Both liquids being at the same level, at b, 
the tube is allowed to remain for a time, 
when it is found that both liquids pass 
through the diaphragm at the bottom of the 
tube, but that this exchange takes place un¬ 
equally , so that the volume of one of the 
liquids increases, while that of the other 
diminishes. The stronger current, whether 
this comes from the liquid of the tube to that 
of the glass, or in the contrary direction, is 
called endosmose , the weaker, exosmose. 
Sometimes the two currents are of the same 
strength, so that the level in both the tube 
and the glass remains unaltered. 

183. Endosmose and exosmose take place, not merely through 
an animal membrane, but also through baked, but unglazed 
or porous earthen-ware, through the stems of plants, and 
through a great number of other substances. When an india- 
rubber bottle is filled with ether, and placed in alcohol, the 
endosmose or stronger current is from the ether to the alcohol, 
and the bottle thus empties itself. If, on the other hand, the 
bottle is filled with alcohol and placed in ether, the endosmose 
of the ether distends the bottle, by augmenting the volume of 
the alcohol. At the same time exosmose takes place, or the 
alcohol passes out of the bottle into the ether, but the current 
in this direction is much weaker. If the bottle is filled with 
ether and placed in water, the ether passes into the water, 
and the contents of the bottle diminish. If filled with alco¬ 
hol, the same effect takes place, though, as mentioned above, 
the bottle thus filled, distends in ether. If water be used to 
fill the bottle, it will distend in either alcohol or ether. En¬ 
dosmose, through india-rubber is, therefore, from ether to alco¬ 
hol or water, and from alcohol to water. 

184. If a bladder be tied over a glass filled with alcohol, 



182. Explain Eig. 66. What is meant by endosmose ?—exosmose 1 

183. Through what substances does endosmose take place ? Mention some 
examples of endosmose through india-rubber* When ether, alcohol, and water, 
are compared, in what way does endosmose take place through india-rubber ? 

























THE ELEMENTS AND THEIR COMBINATIONS. 


139 


and the glass be inverted under water, the endosmose of the 
water to the alcohol is so powerful, that the bladder swells up, 
and when pricked with a needle, the alcohol spirts out in a 
long stream. In this case the endosmose is opposite to what 
it was in the last, being from the water to the alcohol, while 
with india-rubber, it was from alcohol to water. The same 
change of endosmose, occurs between water and ether. 

185. Endosmose is directed from water to solutions of glue, 
gum, sugar, and white of egg; the rise of these liquids in the 
tube, d, (Fig. 66,) when they have the same density with 
each other, is as the numbers, 3, 5, 11, 12, the first number, 
or 3, representing the rise of the solution of glue, the second 
number, or 5, that of gum, the third number, or 11, that of 
sugar, and the number 12, that of the white of egg; the last, 
therefore, causes the greatest endosmose from water. 

186. Diffusion of gases. This principle has already been 
mentioned and partially described (112.) It is not, however, 
confined to the gases which make up the atmosphere, but is 
a property of all gases. Though many of the gases differ 
from each other very greatly in their specific gravities, yet 
they diffuse themselves through one 

another, and form a uniform mix- _ 67 * 

ture. A bottle, a (Fig. 67,) is pro¬ 
vided with a bent tube, £, and laid 
horizontally upon a table. Differ¬ 
ent gases are introduced within this 
bottle, and it is so placed that the 
tube, t, shall be turned downwards, if the gas is lighter than 
the air, and upwards if the gas is heavier than the air. The 
gas is found to escape from the bottle contrary to its specific 
gravity , and its place becomes supplied with air. The com¬ 
parative rapidity with which this takes place in the different 
gases, may be seen from the following table : 

Of 100 volumes of gas there disappeared— 


Hydrogen 

Sp. gr. 

1 

In 4 hours. 
81-6 

In 10 hours. 
94-5 

Light carb. hyd. 

8 

43-4 

62*7 

Ammonia 

8-5 

41-4 

59*6 

Olefiant gas 

14 

34-9 

48*3 

Carbonic acid 

22 

31-6 

47-0 

Sulphurous acid 

32 

27-6 

46-0 

Chlorine 

35*4 

23-7 

39-0 


184. In what way does endosmose take place through bladder ? 

185. To what solutions is endosmose directed from water ? 

186. Is diffusion a property of all gases ? Explain Fig. 67. Which gases 











140 


ELEMENTS OF CHEMISTRY. 


From this table it appears that gases escape the more 
rapidly the lighter they are, and their power of diffusion prob¬ 
ably varies in the inverse ratio of the square roots of their 
specific gravities. Thus 47 measures of hydrogen escaped in 
two hours, and the same volume of carbonic acid in ten. Now 
this ratio of 10 : 2, or 1 : 5, is nearly that of the square root 
of 1 (sp. gr. of hyd.) to the square root of 22, (sp. gr. of carb. 
acid.) 

187. If the bottle contains a mixture of two gases, the 
more diffusible of the two will escape in greater proportion, 
into the air, and the less diffusible in smaller proportion 
than if each gas were contained alone in the bottle. This 
will take place, although the bottle be so placed that gravity 
will favor the less diffusible, and oppose Che more diffusible 
gas, as when hydrogen and carbonic acid are mixed, and the 
bottle containing the mixture is so placed that the tube opens 
downwards. In this case, the hydrogen will escape in greater 
proportion than the carbonic acid, and more rapidly than it 
would if the carbonic acid were not present, while the latter 
will escape less rapidly, on account of the presence of hydro¬ 
gen. In the same manner, if two flasks are connected by a 
tube, as represented on page 69,* and the upper flask is filled 
with equal measures of hydrogen, (sp. gr. 1,) and olefiant gas, 
(sp. gr. 14,) and the lower with carbonic acid, the upper flask 
will, after ten hours, be found to contain only ^ as much hy¬ 
drogen by volume, as the olefiant gas. Though the volumes 
of the hydrogen, and the olefiant gas were at first equal, and 
though hydrogen is 14 times lighter than olefiant gas, it has 
descended into the lower flask 4 times as rapidly as the olefiant 
gas, while carbonic acid, the specific gravity of which is 22, 
and which is therefore heavier than either gas in the upper flask, 
has risen to supply the place of a portion of both these gases. 

188. Mixture of gases likewise takes place when they are 
separated by a porous body or by a cracked glass vessel. Hy¬ 
drogen kept in a cracked receiver, standing over water, escapes 
by degrees through the crack into the surrounding air, and the 
water in the receiver rises to the height of 2|- inches above the 

* The lower flask in this case should be seven times larger than the upper. 


have the greatest power of diffusion ? By what rule may this power be deter¬ 
mined ? How is this illustrated ? 

187 . What effect has mixture on the diffusion of gases ? How is this illus¬ 
trated ? 

188 . Under what other circumstances does the mixture of gases take place ? 
By what facts is this shown ? When the cracked receiver contains hydrogen 
and is surrounded by a receiver containing carbonic acid over mercury -what 



THE ELEMENTS AND THEIR COMBINATIONS. 141 

outer level. With the hydrogen which has not escaped, hut 
still remains in the receiver, 7 per cent, of nitrogen is found 
which has entered by exosmose from the external air. The 
exosmose, in this case, is confined to the nitrogen of the exter¬ 
nal air, for no oxygen is found within the receiver. In the 
same manner hydrogen escapes out of bottles closed even with 
well ground stoppers, if the stoppers are not greased. If the 
cracked receiver, containing hydrogen, be placed over a trough 
of mercury, and covered with an uncracked receiver, contain¬ 
ing carbonic acid, or air, the mercury will rise in the inner re¬ 
ceiver to the height of an inch or two, and sink in the same 
proportion in the"outer. This difference would be still greater, 
but when it amounts to about two inches, the pressure, or 
weight, of the mercury in the inner receiver, draws the air, or 
carbonic acid, from the outer receiver, through the crack, thus 
compensating in volume for the hydrogen which has escaped. 

If the experiment be reversed, and the cracked receiver be 
filled with air, and the outer receiver with hydrogen, the mer¬ 
cury will rise in the outer and sink in the inner, proving that 
the hydrogen makes its way downwards through the inner and 
cracked receiver, contrary to its specific gravity. 

189. If a sheet of india-rubber be tied over the opening of a 
wide-mouthed bottle full of hydrogen gas, 
it is soon pressed imvards, even to burst- Fig. 68. 

ing. If the bottle be filled with air, and F 

placed in an atmosphere of hydrogen, the 
swelling and bursting take place out - 
wards . A well closed bottle of india-rub¬ 
ber, if perfectly empty, does not distend 
when placed in hydrogen gas ; but if it 
contains a small quantity of air, disten¬ 
tion takes place. Almost all other gases 
except nitrogen, exhibit the same rela¬ 
tions towards common air as hydrogen 
does, but in different degrees. To meas¬ 
ure their various powers of diffusion, an 
apparatus, like that represented in Fig. 

68, is employed. A siphon tube, a , is 
funnel-shaped at the shorter arm. A sheet of india-rubber is 
tied over this arm, and the other arm is made very long. 


action is observed ? What is the action when the experiment is reversed, or 
when the outer receiver contains hydrogen and the inner and cracked receiver 
contains carbonic acid ? - ., 

189. When a sheet of india-rubber is tied over the opening ot a wide¬ 
mouthed bottle full of hydrogen gas, the bottle standing in the open air, what 
effect is produced ? What is the effect if the bottle is filled with air and placed 
























142 


ELEMENTS OF CHEMISTRY. 


Mercury is poured into the longer arm, so that it rises in the 
shorter arm, and encloses a portion of air beneath the india-rub¬ 
ber. The shorter arm is then introduced under a receiver, b, 
standing over mercury, and filled with the gas to be examined. 
This gas penetrates the india-rubber, mixes with the air beneath, 
and, increasing its volume, causes the mercury to rise in the longer 
arm, sometimes to the height of 63 inches, or more than twice 
its usual height in the barometer. It might be driven higher 
if the india-rubber could sustain a greater pressure without 
bursting. By experiments of this kind on different gases, it is 
found that the same volume of ammonia passes through the 
india-rubber to the air beneath in 1 minute, as of sulphuretted 
hydrogen in 2\, of carbonic acid in 5 J, of hydrogen in 37^-, of 
oxygen in an hour and 53 minutes. Some of these gases are 
absorbed by the india-rubber, causing it to swell up. Of car¬ 
bonic acid it absorbs an equal volume. 

190. A moist bladder, or moistened gold-beaters’ skin, acts 
like a sheet of india-rubber. A moist bladder, two thirds 
filled with coal gas, or air, swells when suspended in carbonic 
acid gas, and finally bursts. In this experiment as much as 
40 per cent, of carbonic acid sometimes mixes with the coal 
gas, while only a very small quantity of the latter escapes into 
the atmosphere of carbonic acid. If the bladder were perfectly 
dry, it would not distend in carbonic acid ; the endosmose of the 
carbonic acid is, therefore, owing to its absorption by the water 
of the moistened bladder, by which it is transmitted to the 
inner surface of the bladder, and there given up to mingle 
with the air. A bladder moderately wet, expands more than 
one that is thoroughly soaked, for the thinner the film of water 
that absorbs the gas, the sooner will the gas reach the oppo¬ 
site surface. If the bladder containing air be moistened with 
alcohol (which absorbs carbonic acid more readily than water 
does), it will expand in an atmosphere of carbonic acid as 
quickly as if it were moistened with water, but not more so. 
If, on the other hand, the bladder be rubbed with olive oil, or 
oil of anise (neither of which absorbs carbonic acid), it will not 
expand in carbonic acid. In sulphuretted hydrogen a wet 
bladder containing air will expand more quickly than in car¬ 
bonic acid, and after being distended as far as possible in car¬ 
bonic acid, it will expand still further if placed in an atmos¬ 
phere of sulphuretted hydrogen. 


in an atmosphere of hydrogen? Explain Fig. 68. Mention some of the re¬ 
sults obtained by this apparatus. 

190. What facts are mentioned to illustrate the action of moistened bladder ? 
Why is it necessary that the bladder should be moist ? What effect is produced 



THE ELEMENTS AND THEIR COMBINATIONS. 


143 


191. When gases are generated in earthenware retorts, or 
conducted through earthenware tubes, portions of these gases 
escape through the pores, and are replaced by air entering 
from without. When these earthen vessels are placed in the 
fire, nitrogen and carbonic acid enter in place of the gas which 
escapes. If we heat water, hydrate of lime, or moist clay, in 
an earthen retort, either to redness, or just above the boiling 
point of water, very little water is evolved at the end of the 
retort, the greater part escaping through the pores ; but there 
is obtained a great quantity of atmospheric air, which some¬ 
times amounts to T 9 o of the weight of the 
water present, but contains less oxygen and 69 - 

more carbonic acid (derived from the fire), 
than common air. If the retort is inclosed 
in a receiver, (Fig. 69,) standing over mer¬ 
cury, the neck of the retort passing, air-tight, 
through an opening in the top, and heat is 
applied by means of a large lens, a consid¬ 
erable quantity of air issues from the open 
end of the retort, water collects over the 
mercury in the receiver, and this (the mer¬ 
cury) rises 3-J- inches, if the retort is made of compact earthen¬ 
ware, and to a smaller height if it is more porous. The air 
that issues from the end of the retort, is derived in part from 
that which penetrates the retort from the receiver by exos¬ 
mose, while, by endosmose, the watery vapor escapes into the 
receiver, where it is condensed on the surface of the mercury. 
If the receiver contains hydrogen, or nitric oxide, these gases, 
in the same way, issue from the open end of the retort, and 
the mercury also rises in the receiver. From the same cause, 
when the vapor of water is passed through the tube of a 
tobacco-pipe heated to redness, a mixture of gases is obtained, 
differing little from common air. The same phenomena are 
exhibited by vessels, or tubes, of chalk, or white marble. The 
mixing of gases through earthenware retorts, explains the in- 



by moistening the bladder with alcohol ?—1by rubbing it with olive or anise oil ? 
What is the action of a moistened bladder in sulphuretted hydrogen ? 

191. What effect is produced when gases are generated in earthenware re¬ 
torts or conducted in earthenware tubes ?—when these earthen vessels are 
placed in the fire ?—by heating water, hydrate of lime, or moist clay, in an 
earthen retort ? Explain Fig. 69. Whence is the air that issues from the end 
of the earthen retort derived ? Whence is the water that is condensed on the 
mercury obtained ? What effect is produced when hydrogen or nitric oxide 
surrounds the retort in the receiver ? What is the effect of passing the vapor 
of water through the tube of a tobacco-pipe heated to redness? Why did 
chemists formerly suppose that watery vapor was converted into nitrogen in 
passing through red-hot tubes? 













144 


ELEMENTS OF CHEMISTRY. 


correct results which chemists formerly obtained. It was for¬ 
merly supposed that the vapor of water was converted into 
nitrogen gas, by being passed through red-hot tubes. 


192. First law of the combination of gases by volume ?. The volumes in 
which gases unite are in simple equivalent proportion to each other. 
This appears from the column marked I. in the table below. 

Second law. When these gases are in more than one proportion the 
second is a multiple of the first; for example, the equivalent volume of 
nitric oxide in column III. is double that of nitrous oxide. 

Third law. After combination, the volume of the resulting compound 
bears a simple relation to the volumes of the constituents before combi¬ 
nation. This may be seen by comparing columns II. and III. in the 
table. 


W ater. 

Nitrous oxide.. 
Nitric oxide ... 
Sulphurous acid.... 
Sulphuric acid ... 
Sulphuretted hyd 

gen- ...... 

Hydrochloric acid 

Ammonia. 

Calomel (296).... 
Corrosive sublimate 


Formula. 

Eq. Volume 
Constituents. 

of 


I. 


II, 

, HO 

PH 

-H 2 ) = 

3 

NO 

(0,H 

f-N 2 ) = 

3 

. no 2 .... 

(o a 4 

-N 2 ) * 

4 

. SOo .... 

(O 2 4 

-Si) - 

7 

.so; .... 

(<M 

-SI)- - 

10 

. HS 

(H 2 +S1|) = 

7 

cm .... 

(H 2 +C1 2 ) = 

4 

. nh 3 .... 

(h 3 +n); = 

4 

. Hg 2 Cl .... 

(Cl 2 - 

f-Hg 4 ) = 

6 

Hg Cl .... 

(C1 4 - 

fHg 4 ) = 

8 


Eq. Volume of 
Compounds. 

III. 

. 2 . 

. 2 . 

.4. 

. 6 . 

. 6 . 

. 6 . 

.4. 

.4. 

. 6 . 

.4. 


METALLIC ELEMENTS. 

193. The metals are fifty-four in number. Of these, seven, 
viz., gold, silver, mercury, copper, iron, tin, and lead, were 
known to the ancients ; the remainder have been discovered 
within a period comparatively recent, and most of these within 
the last half century. 

The properties of metals may be divided into the gen¬ 
eral properties , or those which are common to all metallic 
bodies, and distinguish them from bodies not metallic, and the 
peculiar properties , or those which belong to and characterize 
particular classes of metals. 


193. What is the number of metals at present known 1 How many of these 
were known to the ancients ? How may the properties of the metals be di¬ 
vided ? State the general properties of metals. With what is the peculiar 
lustre of metals connected ? How may this lustre be destroyed ? How may 

























THE ELEMENTS AND THEIR COMBINATIONS. 


145 


The general properties of metals are: (1.) They are all 
conductors of heat and electricity, but when obtained in a pul¬ 
verulent state, their power of conducting heat and electricity is 
small. (2.) All metals possess a peculiar lustre, so character¬ 
istic as to be called the metallic lustre. This property is 
doubtless connected with an extraordinary degree of opacity 
which the metals present in every instance. The thinnest 
leaves or plates of most metals arrest the passage of light in the 
most complete manner ; but very thin gold-leaves admit the 
passage of light through their substance , as is proved by the 
peculiar properties which this transmitted light possesses. 
The metallic lustre is destroyed by every cause which breaks 
the continuity of the surface, as when the metals are reduced 
to powder, or when a rough surface is produced by casting. 
In the latter case it may sometimes be restored by pressure 
with a burnisher, as in castings of gold and silver. (3.) All 
the metals combine with oxygen, and, when thus combined, 
they generally lose their metallic lustre. (4.) When the com¬ 
pounds of the metals are submitted to the action of galvanism, 
the metals appear at the negative pole of the battery. (5.) All 
the metals are combustible. Zinc burns with a brilliant 
flame, when heated to redness in the open air ; iron burns 
splendidly in oxygen gas, and the most refractory metals burn 
under the flame of the oxy-hydrogen blowpipe. 

Among the peculiar properties of metals, or those properties 
which belong not to all, but to certain classes of metals, are : 
(1.) Malleability, or the property of being extended under the 
blows of the hammer. (2.) Laminability, or the property of 
being rolled out into sheets. Tin and platinum are easily 
rolled out into foil. Silver bars are rolled out into strips, for 
the manufacture of spoons and coin. Iron and zinc are rolled 
out into sheets. (3.) Ductility, or the property of being drawn 
out into wire. Nearly all the malleable metals are also duc¬ 
tile ; but this is not always the case. Iron, for example, can¬ 
not be beaten out into thin laminae, but it may be drawn into 
fine wire. Dr. Wollaston devised a method by which gold 
wire might be obtained, so fine that its diameter was only 
_ of an inch, and 550 feet of it weighed only a grain. He 
obtained a platinum wire so fine, that its diameter did not ex¬ 
ceed ¥i7r Vo of an ineh. (4.) Metals differ very mueh in their 
tenacity. This is measured by the number of pounds required 
to draw apart wires of the same size but of different metals. 


it be in some cases restored ? What effeet has combination with oxygen upon 
the lustre of metals ? What is the action of galvanism upon the compounds ot 
metals 1 What examples are given of the combustion of metals ! btate tne 




146 


ELEMENTS OF CHEMISTRY. 


The comparative tenacity of some of the metals is represented 
by the numbers in the table below— 


Iron 

250. 

Gold 

68. 

Copper 

137. 

Zinc 

50. 

Platinum 

125. 

Tin 

16. 

Silver 

85. 

Lead 

12 . 


The same metal varies in its tenacity according to its purity, and ac¬ 
cording to the manner in which it has been worked. The quality of the 
metal determines in a great measure its tenacity. 

(5.) Metals differ very much in their specific gravities. Po¬ 
tassium and sodium are lighter than water, while platinum is 
nearly 21 times heavier than that fluid. 


Table of specific gravities of metals at 60°. 


Platinum 

20-98. 

Bismuth 

9-82. 

Zinc 

6-86 to 7-1. 

Gold 

19-26. 

Copper 

8-89. 

Manganese 

6-85. 

Tungsten 

17-60. 

Cobalt 

8-54. 

Antimony 

6-07. 

Mercury 

13-57. 

Arsenic 

5-88. 

Titanium 

5-30. 

Lead 

11-35. 

Iron 

7-79. 

Sodium 

0-972. 

Silver 

10-47. 

Tin 

7-29. 

Potassium 

0865. 


(6.) Metals differ as much in fusibility as in density. 


Class I.— Metals fusible below a red heat (1,000°.) 


Mercury —39°. 

Potassium 136°. 

Sodium 190°. 

Tin 452°. 


Bismuth 497°. 

Lead 612°. 

Zinc 773°. 

Antimony just below redness. 


Class II.— Metals infusible below a red heat. 

Silver 1873°. I Gold 2016°. 

Copper 1996°. | Cast iron 2786°. 


Class III.— Metals difficult of fusion in a wind furnace. 

££&»* SS5&. \ ****** “ 

Class IV.— Metals infusible in a wind furnace, fusible by the oxy-hydro- 

gen blowpipe. 

Titanium. I Rhodium. 

Iridium. | Platinum, 


properties which are peculiar to classes of metals. What six metals possess 
the property of welding ? To what is this property owing \ Mention some of 
the volatile metals ? 







THE ELEMENTS AND THEIR COMBINATIONS. 147 

Some metals acquire a pasty or adhesive state, before be¬ 
coming fluid. This is the case with iron and platinum, silver 
and gold, and with sodium and potassium. It is this peculi¬ 
arity which confers the valuable property of welding-, by which 
pieces of iron and steel are united without solder, and finely 
divided platinum sponge is converted into a solid and compact 
bar. 

(7.) Volatility is possessed by some of the metals, and, per¬ 
haps, by all, could temperatures sufficiently elevated be ob¬ 
tained. Mercury boils and distils below a red heat; potassium 
and sodium, and zinc and cadmium, rise in vapor, when 
heated to bright redness ; mercury, arsenic, and tellurium are 
volatile. 

(8.) The metals differ greatly in their attraction for oxygen. 
Potassium and sodium are oxidized by mere exposure to the 
air, and they decompose water at all temperatures when they 
come in contact with it, taking from the water its oxygen by 
which they are oxidized. Iron and copper may be exposed in 
dry air without change, but they are slowly oxidized, by expo¬ 
sure to a moist atmosphere, and combine rapidly with oxygen, 
when heated to redness in the open air. The affinity of cop¬ 
per for oxygen is less than that of iron, and that of mercury is 
less than that of copper. Pure mercury does not attract 
oxygen-from the air, but its amalgams quickly become oxidized. 
Gold will bear the most intense heat of a wind furnace with¬ 
out oxidizing. 

(9.) Many of the metals have a structure decidedly crys¬ 
talline. Iron is fibrous ; zinc, bismuth, and antimony, are 
lamellated, or crystallized in thin plates. Gold, silver, and 
copper, occur naturally in crystals, and other metals crystallize 
when they are gradually cooled from the melted to the solid 
state. 

. 194. Metallic Combinations. These are of two kinds; 
those formed by the union of the metals among themselves, 
and'Compounds with the non-metallic elements. The former 
are called alloys, or amalgams, where one of the metals is 
mercury. The latter are called oxides, chlorides, sulphurets, 
&c., according as the non-metallic element is oxygen, chlorine, 
sulphur, &c. When an acid is united to an oxide, the result¬ 
ing compound is called a salt. These salts and oxides will be 
conveniently considered under the metals to which they 
belong. 


194. Of what two kinds are metallic combinations ? What is meant by the 
term alloy ?—amalgam ?—oxide, chloride, sulphuret, &c. 1 —metallic salt ? 




148 


ELEMENTS OF CHEMISTRY. 


195. The metals are arranged according to the relations of 
their oxides to the reagents employed in chemical analysis.* 

First Group. The Alkalies. 

Metals —potassium, sodium, ammonium. 

Oxides —potash, soda, ammonia;—not precipitable by sulphuretted 
hydrogen, nor by hydrosulphuret of ammonia, nor by the alkalies, ( i. e. 
by each other.) 

The metals of this group are lighter than water. They decompose 
water at ordinary temperatures, with liberation of hydrogen. Their 
compounds with chlorine, bromine, iodine, sulphur, and oxygen, are solu¬ 
ble in water, as are also the combinations of their oxides with most acids. 

Second Group. The Alkaline Earths. 

Metals —barium, strontium, calcium, magnesium. 

Oxides —baryta, strontia, lime, magnesia;—not precipitable by sul¬ 
phuretted hydrogen, nor by hydrosulphuret of ammonia, but precipitable 
by alkaline carbonates and phosphates. 

With carbonic and phosphoric acids, the oxides of these metals form 
compounds that are insoluble in water, in which respect they differ from 
the oxides of the last group. The metals of this, like those of the last 
group, decompose water, and their compounds with oxygen and sulphur 
are soluble in water, though less so than those of the alkaline metals. 

Third Group. 

Metals —aluminum, chromium. 

Oxides —alumina, chrome ;—not precipitable by sulphuretted hydro¬ 
gen, precipitable by hydrosulphuret of ammonia. 

The oxides of these metals are insoluble in water, in which they differ 
from the metallic oxides of the previous groups. These metals also do 
not decompose water, unless it contains a free acid. 

Fourth Group. 

Oxides of manganese, iron, zinc, nickel, cobalt;—not precipitable by 
sulphuretted hydrogen in solutions containing a free acid , but precipita¬ 
ble from alkaline solutions. 

These metals, like those of the last group, decompose water in the 
presence of acids, with evolution of hydrogen. The oxides of this group, 
with the exception of the oxide of zinc, are insoluble in solutions of 
potash, in which they differ from the oxides of the preceding group. 

Fifth Group. 

. Oxides of bismuth, copper, lead, mercury, cadmium, silver ;— precip¬ 
itable by sulphuretted hydrogen. r 


.. A J er y interesting senes of experiments may be given in illustration of 
this table ; this series may be more or less full according to circumstances It 
will be unnecessary at present to commit the table to memory, as questions on 
the peculiar properties of each group will be given after the metals of that group 





THE ELEMENTS AND THEIR COMBINATIONS. 


149 


The oxides and sulphurets of these metals possess the properties of 
their bases, in which they differ from the metals of the next group, 
whose compounds with oxygen aud sulphur possess the properties of 
•acids. . r 

Sixth Group. 

Tin, antimony, arsenic, gold, platinum;— not precipitable by sulphu¬ 
retted hydrogen from alkaline solutions, but precipitable from acid solu¬ 
tions. (See fourth group.) The precipitate is re-dissolved by adding 
an excess’ of hydrosulphuret of ammonia, which is not the case with the 
precipitated sulphurets of the last group.* 


METALS OF THE ALKALIES. 
Potassium, 0.865. 39. K. 

196. At the head of each of the metals will be placed the 
name of the metal, its specific gravity, its combining number, 
and its symbol, in this order. Thus, this metal is potassium, 
its specific gravity is 0’865, its combining number is 39, and its 
symbol is K. 

The properties of potassium are so remarkable, that it was 
for some time doubted whether it could be placed among the 
metals. One of its most remarkable properties is its lightness, 
which enables it to float on water. Another of its striking 
properties is its intense affinity for oxygen. ( 107 ) In this re¬ 
spect it probably surpasses all other bodies, and is, therefore, fre¬ 
quently used in decomposing metallic oxides otherwise not easy 
of reduction. It absorbs oxygen from both air and water, burn¬ 
ing when thrown on water, and becoming tarnished when ex¬ 
posed to the air. It is therefore kept under naphtha, a fluid 
which contains no oxygen. Its melting point is very low. It 
becomes soft at 80°, and perfectly fluid at 150°. In color and 
lustre it resembles mercury. It crystallizes, by sublimation, in 
cubes, and its cut surface exhibits cubical markings. At 32° 
it is brittle ; at 66° it is as soft as wax. It sublimes in green 
vapors at a temperature below redness. Potassium forms an 
amalgam with mercury. ( 108 ) 

* At the end of the metals (328) will be found a complete list of these bodies 
with their specific gravities, combining numbers, and symbols. 


196. Write the specific gravity, combining number, and symbol of potassium. 
What are some of the most striking properties of this metal ? Mention some 
of the other properties of potassium. 




150 


ELEMENTS OF CHEMISTRY. 


197. Hydrate of potash, caustic potash, KO, HO. When 
a solution of carbonate of potash is boiled with quicklime, the 
lime takes the carbonic acid, and the potash is reduced to its 
caustic state. 

KO, C0 3 =carbonate of potash. 

CaO =lime. 

Bring down the C02 to the CaO, and there is produced 

CaO, C0 2 = carbonate of lime, insoluble. 

[precipitates from solution.] 

KO = Caustic potash. 

[remains in solution. ] 

The hydrate of potash is also formed when potassium is ex¬ 
posed to moist air, which is rapidly oxidized, and at the same 
time absorbs moisture. 

Pure hydrate of potash, is a white, hard, brittle substance, 
very deliquescent ( 109 ), and soluble in water. Alcohol also 
dissolves it freely, which is the case with comparatively few 
of the compounds of potassium. Alcohol may, therefore, be 
used to purify the solid hydrate of commerce. It melts below 
redness, and volatilizes at a full red-heat in white pungent 
vapors. For this reason coal ashes possess less of this valuable 
ingredient for plants than wood ashes, and are, therefore, less 
valuable as a manure for plants than the latter. The solu¬ 
tion of this substance possesses in the very highest degree the 
properties termed alkaline, and, therefore, of all the bases, it 
possesses the strongest affinity for most of the acids (2d law of 
affinity, page 57). It neutralizes completely the most power¬ 
ful acids, and is most destructive of all the alkalies to organic 
substances The alkaline reaction usually predominates in its 
salts formed with the weaker acids. It is con- 

!Fig.70. stantly employed by surgeons as a cautery, for 
which purpose it is moulded into sticks. 

In the solid state, and in solution, hydrate of 
potash rapidly absorbs carbonic acid from the 
( ) air; hence it must be kept in closely stopped 

bottles. This solution is employed in analysis 
/ \ where the quantity of carbonic acid contained 

/ t ^ ie k°dy under examination is to be deter- 

mined. The arrangement is represented in 
Fig.* * 70. The gas from the substance under 
examination, enters the tube at a, and passes through the 


197. Write the symbol of caustic potash. In this symbol what does KO 
stand for? Ans.—The oxide of potassium or potash. What does HO stand 
for? Ans.—water. How then is the whole symbol to be interpreted ? Ans— 
The hydrate* of the oxide of potassium, or the hydrate of potash. How is caus- 

* From a Greek word, meaning water. 



THE ELEMENTS AND THEIR COMBINATIONS. 


151 


three lower bulbs, which are about two thirds filled with so¬ 
lution of'caustic potash. This solution absorbs all the carbonic 
acid from the gas which then passes off through the tube, b. 
The bulbs, with the potash solution, are weighed before and 
alter the process, and the increase in weight shows the amount 
of carbonic acid absorbed. 

The water of the hydrate of potash cannot be displaced by, 
heat, the whole compound volatilizing at a very high tempera¬ 
ture. This is, therefore, called the water of constitution (see 
questions, p. 97.) 

198. Carbonate of potash, KO, C0 2 -f2H0. T-his substance 
is the common potash of the shops. It is obtained by the fol¬ 
lowing, or a similar process : 

Water is poured upon wood ashes, and the mixture stirred 
till the potash, (carbonate of potash,) contained in these ashes, 
is dissolved. The mixture is then allowed to stand, when the 
greater part of the solid matter settles and the clear liquor is 
poured off. This is boiled down until it becomes quite thick, 
so as hardly to be liquid. It is now allowed to cool, and, 
when, cooled, it becomes a solid mass of carbonate of potash. 
In this state, it is called gray salts. This is dissolved and 
boiled down a second time, when it forms what is called i&hite 
salts. When pulverized, this constitutes pearlash. 

Carbonate of potash, though found in the ashes, is not con¬ 
tained in the wood of plants. In all land plants, potash exists 
in combination with a vegetable acid. This aeid is converted 
by burning the plants, into carbonic acid, and the potash thus 
left in the state of a carbonate. Potash is contained very un¬ 
equally in plants. Shrubs contain three times, and herbs five 
times as much saline matters as trees, and in the latter, the 
leaves are more productive than the branches, and the branches 
than the trunks. 


The ashes from one ton of 

Pine wood gave.. 

Poplar. 

Bireh.. 

Beech. 

Beech bark. 

Oak. 

Oak bark. 


*90 lbs. of potash. 
1-50 “ 

■ 2-58 “ 

2:90 « 

12*00 “ 

4*06 “ « 

4-16 “ 


tic potash prepared 1 Explain Fig. 70. What is said of the water of the hy¬ 
drate of potash ? 

198. Write the symbol of the carbonate of potash. How is this symbol to 
be interpreted 1 Ans.—The carbonate of the oxide of potassium+ 2 eq. of water, 
or the carbonate of potash + 2 eq. of water. How is carbonate of potash ob¬ 
tained ? Is this salt contained in the wood of plants ? Why is it found in 
the ashes ? State some of the properties of carbonate of potash. 










152 


ELEMENTS OF CHEMISTRY. 


Willow. 

Elm. 

Maple. 

Wheat straw. 

Barley straw. 

Corn Stalks. 

Bean stalks. 

Dry oak leaves 
Young wheat stalks 
Dried potato stems 
Angelica. 

From this table it is evident that potash is of great value in agricul¬ 
ture. By such crops as corn, wheat, potatoes, tfcc., immense quantities 
of potash are carried from the soil, and this would, therefore, be soon 
exhausted were it not supjilied partly by the constant decomposition of 
feldspar * in the soil, and partly in the manures whieh are spread upon 
the land. 

It is also evident from this table that ashes must form a valuable ma¬ 
nure, for it is the great principle of agriculture, that plants require 
from the soil or the atmosphere those elements of which, they are composed, 
or those elements which are obtained by their analysis. Even leached 
ashes are of value to the farmer, for, besides the potash whieh still re¬ 
mains in these ashes, they contain other substances of great value to 
plants. 

Potash combines with and renders soluble the vegetable matter of the 
soil, so as to bring this into a state in which it may be readily assimi¬ 
lated by plants. It promotes certain changes in plants, to be described 
hereafter, whieh are essential to the production of the living vegetable, 
and its presence in the soil enables it to obtain a supply of nitrogen 
from the atmosphere, and to bring this nitrogen in the form of nitric 
acid to the roots of plants. 

Carbonate of potash is extremely deliquescent, and soluble 
in less than its own weight of water at 60 a . Its solution 
is highly alkaline to test-paper. It is insoluble in alcohol. 
By heat, the water of crystallization is driven off, and, by a 
temperature of full ignition, the salt is fused, but the carbonic 
acid is not expelled, as it is from most of its combinations by 
heat. The vapor of water passed over it at a red-heat decom¬ 
poses it, forming hydrate of potash, and setting free the car¬ 
bonic acid. When heated to whiteness with charcoal, it is 
also decomposed, and the metal potassium is reduced with the 
evolution of carbonic oxide gas. 

199. Bicarbonate of potash, KO, C0 2 ,+H0, C0 2 . This 

* A single cubic foot of feldspar, according to Liebeg, is sufficient to supply 
an oak copse covering a surface of 26,910 square feet, with the potash required 
for five years. In feldspar potash exists as a silicate, which by the action of 
water containing carbonic acid , is gradually dissolved, and thus taken up by 
plants. 


5'V0 lbs. of potash. 

. 1-80 

(t 

u 

. 7-80 

U 

ti 

8-36 

u 

« 

. 11*60 

a 

u 

. 35-00 

a 

a 

. 40-00 

a 

a 

. 48-00 

a 

a 

. 94-00 

i* 

u 

. 11000 

u 

a 

. 192-40 

a 

u 


199. Write the symbol of bicarbonate of potash. How is this symbol to be 














THE ELEMENTS AND THEIR COMBINATIONS. 


153 


salt requires for its solution 4 parts of cold water, at 60°, and 
less water at 212°. The solution is nearly neutral to test- 
paper, and has a much milder taste than the carbonate of pot¬ 
ash, for which reason it is more often used in medicine. It 
forms large, beautiful crystals. These are very easily decom¬ 
posed ; for when they are heated they evolve water and a por¬ 
tion of their carbonic acid, and are thus converted from the 
bicarbonate to the carbonate of potash. The solutions of this 
salt decompose by evaporation at all temperatures, losing car¬ 
bonic acid, and being converted into a neutral carbonate of 
potash. 

200. Nitrate of potash, nitre, saltpetre, KO, N0 5 . This 
important compound is a natural product, being disengaged by 
a kind of efflorescence from the surface of the soil in certain 
dry and hot countries. Nearly all the nitre of commerce 
comes from India, where it is a natural product. In France, 
large quantities of artificial nitre are prepared, by mixing 
masses of putrid animal matter with lime. The nitrogen of 
the decaying animal matter unites with the lime to form ni¬ 
trate' of lime ; this is afterwards mixed with carbonate of pot¬ 
ash, when a double exchange takes place : 

KO, C0 2 =carbonate of potash. 

CaO, N0 5 =nitrate of lime. 

By double exchange. 

KO, NO_ = nitrate of potash, soluble salt. 

[dissolved out from the insoluble carbonate of lime.] 

CaO, C0 o =carbonate of lime, insoluble salt. 

[remains after the nitre is dissolved out.] 

The symbol for nitre, KO, NO s , shows a very large amount 
of oxygen. The equivalent of K is 39 (196.), that of 0 is 8 
(122.), and that of N is 14 (122). We find, therefore, the 
relative quantities of each of these bodies in the following 
way : 

K =39. 

O = 8, 8 

N =14. 

0 5 =40,40 
101,48 

In every 101 parts of nitrate of potash there are 39 parts 


interpreted 1 Ans.—Carbonate of potash with an eq. of carbonated water. 
State some of the properties of this salt. . 

200. Write the symbol of nitrate of potash. Explain this symbol. Explain 
the diagram. How much potassium is contained in 101 parts of nitrate of 
potash?—How much potash?—How much oxygen ? how much nitrogen. 
To what is the great power which this salt possesses in supporting combustion 
owing ? 


7 * 





154 


ELEMENTS OF CHEMISTRY. 


of K, or potassium ; 39 + 8=47 parts of KO, or potash ; 48 
parts of oxygen, and 14 parts of nitrogen. On account of the 
large quantity of oxygen which this salt contains, and the 
feeble affinity with which this oxygen is held , the salt has 
great power in promoting combustion. A weak solution, 
poured over cloth or paper, will cause them when dry to burn 
rapidly on applying a lighted coal. For the same reason, nitre 
is employed in the manufacture of gunpowder. The following 
table shows the composition of three different kinds of pow¬ 
der : 



Nitre. 

Sulphur. 

Charcoal. 

Common powder, 

75 

m 

12J. 

Shooting powder, 

78 

10 

12. 

Blasting powder, 

65 

20 

15. 


201. When gunpowder is fired, the oxygen of the nitre is 
transferred to the carbon, forming carbonic oxide, and carbonic 
acid (chiefly the latter,) the sulphur forms with the potassium 
sulphuret of potassium, and the nitrogen is set free. The 
large volume of gas from the nitrogen and the carbonic oxide, 
is still further expanded by the very high temperature, and 
produces the powerful explosive effects of gunpowder. Tlie 
gas evolved, when measured cold, is about 300 times the gun¬ 
powder in volume, but, from its high temperature, it is proba¬ 
ble that it expands at least 1,000 times. Its instantaneous 
combustion, and, consequently, its explosive energy, depends 
upon its granulation , for when powder is not granulated, or 
when the granulation is destroyed, the gunpowder burns 
rapidly, but without explosion. By granulation the flame is 
able to penetrate the whole mass more rapidly, and to produce 
an explosion nearly instantaneous. Still, the discharge of gun¬ 
powder occupies a perceptible interval of time, as may be 
shown by burning a line of powder in connection with a paral¬ 
lel line of some fulminating powder, as fulminating mercury, 
of equal length. The line of common powder will occupy a 
perceptible interval in its discharge, while that of fulminating 
powder will appear to flash instantaneously. Mining and 
blasting powder is frequently mixed with a considerable 
quantity of sawdust, the object of which is to prolong the dis¬ 
charge, and thus to render the powder more effectual. Ful¬ 
minating powders are found not to be adapted for fire-arms, 


201. When gunpowder is fired, what gases are formed 7 What solid sub- 
stance is formed ? Acs—Sulphuret of potassium, a salt of dark gray color 
which, blackened with carbon, is the residue left by the explosion ofgunpow- 
dei\ How much does the gas evolved in the explosion of gunpowder exceed 
in bulk the powder ? Upon what does the instantaneous explosion of powder 



THE ELEMENTS AND THEIR COMBINATIONS. 


155 


for their explosion is so nearly instantaneous, that the effect 
which they produce is almost wholly local, bursting 1 the mus¬ 
ket without projecting the ball. A sustained effort is found 
necessary to the best effect, both in fire-arms and in blasting 
rocks. The best powder is so made as to bum in about 
the time that the ball traverses the barrel of the gun or can¬ 
non. 



In nearly all fire-works, nitre is employed to supply oxygen 
for the ready combustion of the various materials.( no ) Nitre is 
also largely used in freezing mixtures to generate cold.( ni ) 
Its crystalline form is very beautiful (Fig. 71.) It is crys¬ 
tallized by cooling a hot saturated 
solution in a bottle, or on a slip of 
glass. The crystals are anhydrous, 
but they often hold a portion of li¬ 
quid mechanically lodged within 
their substance. As this is particu¬ 
larly the case with large crystals, it 
is sometimes necessary to agitate the 
solution while crystallizing, to obtain 
small crystals, for the liquid en¬ 
closed in the larger crystals becomes 
a^source of impurity. Crystals of a 

large size crack with the warmth of $he hand. Their taste is 
sharp, bitter, and cooling. They are fusible into a limpid li¬ 
quid by a heat under redness. Their solution has considera¬ 
ble antiseptic properties, and is therefore sometimes employed 
in preserving meats, especially beef, to which it communicates 
a red color and considerable firmness. Both the nitrogen and 
the potash of nitrate of potash are of great value in agriculture, 
but the first of these constituents may be obtained in a cheaper 
form, and probably in a form better adapted to plants from 
ammonia, and the second also more cheaply from ashes. 

202. Chlorate of potash, KO, C10 5 . Oxygen is the chief 
constituent of this salt, and is held by a very weak affinity. 
To this fact are to be ascribed its peculiar and striking prop¬ 
erties. On the application of heat it is decomposed, affording 
pure oxygen. With certain bodies it unites to form explosive 
compounds, some of them of the most terrible kind. With 


depend ? How does granulation produce this effect 7 Is the discharge of gun¬ 
powder absolutely instantaneous ? How may this be shown ? Why are not 
fulminating powders suitable for fire-arms ? For what purpose is nitre em¬ 
ployed in fire-works 1 What does Fig. 71 represent ? What are some of the 
properties of crystallized nitre ? , . , . , , , ,, 

202. Write the symbol of chlorate of potash. Explain this symbol (chlorate 
of the oxide of potassium, or potash.) How much oxygen does the symbol ol 






156 


ELEMENTS OF CHEMISTRY. 


other combinations it explodes by friction, and is, therefore, now 
a large article of commerce, being employed with phosphorus 
in the manufacture of matches. When in powder it detonates 
with a blow, hence it should be pulverized with care, and 
when ground very fine, it should always be previously moist¬ 
ened with water, as it may explode by merely rubbing or 
pounding. It forms, also, compounds that take fire with acids. 
The percussion powder is a mixture of chlorate of potash with 
sulphur, or other combustibles. 

Chlorate of potash is soluble in about 20 parts of cold and 
2 of boiling water. Its crystals have a pearly lustre, and are 
flat, tabular, and anhydrous. Their taste is cooling, and 
slightly bitter, resembling the taste of nitre. From the great 
amount of oxygen which it contains, chlorate of potash imparts 
a bright scarlet color to the venous blood, and is used in medi¬ 
cine as a remedy for certain fevers. 

203. The salts of potash are more or less soluble in water, 
and are distinguished by a white, crystalline precipitate, formed 
with tartaric acid, The precipitate is not usually formed 
until sometime after the tartaric acid is added, and this effect 
is greatly promoted by agitation. The most important of the 
liquid tests for potash, is that with the chloride of platinum, 
which throws down, in a concentrated solution, a yellow crys¬ 
talline precipitate. The solution in this case should not be 
alkaline, but rendered neutral, or acid, by the addition of hy¬ 
drochloric acid. Ammonia produces a similar precipitate, but 
the compounds of ammonia are easily distinguished from those 
of potash. The former, when heated, especially with quick¬ 
lime, lose their ammonia, which is known by its smell, and its 
reaction with hydrochloric acid (p. 137), while potash remains 
fixed. The delicacy of the tests with chloride of platinum and 
tartaric acid, is increased by the addition of alcohol. Salts of 
potash also give a characteristic purple tint to the outer blow¬ 
pipe flame. 

Sodium, 0-972. 23. Na.* 

204. Sodium is a silver-white metal, with a high lustre- 

* Latin, natron, soda. 


chlorate of potash show That it possesses 1 —how much potassium ?—how much 
potash ?—bow much chlorine ? (p. 89.) To what are the peculiar properties of 
this salt to be ascribed 1 Mention some of these properties. 

203. What are some of the tests for the salts of potash ? 

204. Write the specific gravity, combining number, and symbol of sodium. 
Mention some of the properties of this metal. 



THE ELEMENTS AND THEIR COMBINATIONS. 


157 


It greatly resembles potassium in every respect. It is soft 
at common temperatures, melts at 194°, and oxidizes very 
rapidly in the air. Like potassium, it floats on water, but 
does not decompose the water with as great energy as that 
substance. On cold water it floats about without burning ; 
but on hot water it takes fire, burning with its characteristic 
yellow flame, and giving rise to a solution of soda.( m ) 

205. Hydrate of soda, caustic soda, NaO, HO. The pro¬ 
cess by which caustic soda is obtained, is precisely similar to 
that lor caustic potash (200.) Carbonate of soda is boiled 
with quicklime ; the lime takes the carbonic acid, and the 
soda is reduced to the caustic state : 

NaO, C0 2 —carbonate of soda. 

CaO =lime. 

Bring down the C02 to the CaO, and there is produced 

NaO = Caustic soda. 

[remains in solution.] 

CaO, C0 2 =carbonate of lime, insoluble salt. 

[precipitated from solution.] 

206. Sulphate of soda, Glauber's salts, NaO, S0 3 +10 HO. 
Sulphate of soda is the substance left in the retorts used for the 
manufacture of hydrochloric acid, or any process where sul¬ 
phuric acid is added to common salt (p. 103.) Its crystalliza¬ 
tion is exceedingly beautiful, resembling that of nitre, (Fig. 
71.) The crystals contain 10 eq. of water, and are efflores¬ 
cent, and undergo watery fusion when heated. They are solu¬ 
ble in twice their weight of cold water, and rapidly increase 
in solubility, as the temperature of the liquid rises to 91-5°, 
when a maximum is reached. At this temperature 100 parts 
of water dissolve 322 parts of the salt. Heated beyond this 
point, the solubility diminishes, and a portion of the sulphate 
is deposited. A warm, saturated solution, evaporated at a 
high temperature, deposits opaque, prismatic crystals, which 
are anhydrous. 

This salt is purgative, and is therefore sometimes used in 
medicine, although, on account of its very nauseous and bitter 


205. Write the symbol of caustic soda. How much sodium does caustic soda 
contain ?—how much soda ?—how much hydrogen ? (p. 80)—how much water 
(HO) 1 —how much oxygen ? Explain this symbol. State the process for pre¬ 
paring soda. Explain the diagram. What are some of the properties of hy¬ 
drate of soda 1 

206. Write the symbol for sulphate of soda. Explain this symbol. How 
much sodium does the sulphate of soda contain ?—how much soda 1 —how much 
sulphur ? (p. 84,)—how much sulphuric acid (SO 3 ) 1 —how much water ?—how 
much oxygen ? How is this salt obtained ! What is said of its crystallization 
and other properties T What is said of its use in medicine ? 



158 


ELEMENTS OF CHEMISTRY. 


taste, it is almost superseded by sulphate of magnesia. It is 
also called Glauber’s salts, from the physician who discovered 
it. It is found in many mineral waters.( n3 ) + 

207. Carbonate of soda, NaO, CO 2 -j-10 HO. The crys¬ 
tallized carbonate of soda contains the same large proportion 
of water (10 HO) as the crystallized sulphate. This is the com¬ 
mon soda of the shops. It was formerly obtained from the 
ashes of sea-weed. 

The barilla, a coarse kind of carbonate of soda, sometimes employed in 
soap-making, is made from several varieties of sea-weed, that grow on the 
coast of Spain. It is usually manufactured from common salt. The salt 
is first converted into the sulphate, by the addition of sulphuric acid. 
The hydrochloric acid driven off in this process, is saved by being passed 
through water. The sulphate of soda thus made* is reduced to powder, 
and mixed with an equal weight of ground chalk or limestone (carbonate 
of lime,) or lime and sawdust, and half as much crushed coal. This mixture 
is heated to fusion in a furnace, with constant stirring. When the decom¬ 
position is judged complete, the melted matter is raked from the furnace 
into an iron trough, where it is allowed to cool. When cold, it is broken 
up into little pieces, and lixiviated with cold, or tepid water. The sul¬ 
phuric acid of the sulphate of soda, is transferred by double decomposi¬ 
tion to the lime, forming sulphate of lime, an insoluble salt; the carbonic 
acid of the carbonate of lime uniting with the soda, forms carbonate of 
soda, which being soluble, is dissolved out by lixiviation from the insolu¬ 
ble sulphate of lime: 

NaO, S0 3 =sulphate of soda. 

CaO, C0 2 —carbonate of lime. 

By double exchange 

Na0,C0 2 =Carbonate of soda. 

[dissolved out by lixiviation.] r 

CaO, S0 3 =:sulphate of lime, insoluble salt. 

The solution of carbonate of soda thus formed, is evaporated to dry¬ 
ness, and the salt calcined with a little sawdust in a suitable furnace. 
The product is the soda-ash of commerce. About 50 per cent, of this 
is pure carbonate of soda. By dissolving soda-ash in hot water, filtering 
the solution, and then allowing it to cool slowly, the carbonate is deposit¬ 
ed in large transparent crystals. 

208. The roasting of the sulphate of soda with lime is per¬ 
formed in a furnace of peculiar construction, which is often. 

* This is sometimes obtained in the manufacture of salt, by cooling down the 
temperature of a solution, as sea-water, after the salt has been collected , in win¬ 
ter to 38° or 39° when the sulphate of soda crystallises out. In summer, on 
the other hand, sulphate of. magnesia crystallizes out from the solution after the 
salt has been collected. 


207. Write and explain the symbol of carbonate of soda. How was this salt 
formerly obtained ? From what is it now manufactured 1 State this process, 
and explain the diagram. 

208. Explain Fig- 72. What are these furnaces called ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


159 



used for similar processes in the arts. In Fig. 72, a is the 
grate, b the ash-pit, c the chimney, d d the hearth for receiv¬ 
ing the mixture, i the aperture for throwing in the mixture, 
and g an opening for stirring 
it, and scooping it out. These Fig. 72 - 

are called flame f urnaces, or 
reverberatory furnaces, be¬ 
cause the heating is not effec¬ 
ted by the ignited coal of the 
fuel, but by the flame passing 
over the bridge f By this 
arrangement the substance 
heated, or roasted, is kept free 
from the ashes of the fuel. 

209. In the manufacture of glass, potash or soda forms 
the basis. Grlass is a silicate of potash or soda, or a compound 
of silicic acid and potash, or soda. To the silica and soda, or 
potash, a variety of substances are added, to make the glass 
more colorless, dense, and transparent. Lead promotes fusi¬ 
bility, confers density and lustre, and gives tenacity to the 
glass while red hot. It enables the glass to bear sudden 
changes of heat and cold, and improves its refractive power, by 
which it is rendered more valuable in the manufacture of op¬ 
tical instruments, as the microscope, telescope, &c. Black ox¬ 
ide of manganese is used to destroy the slight green color 
given by impure potash or soda. Unless 
used in very minute quantity, it imparts a 
purple tint to the glass. Arsenic is also 
sometimes employed. The ingredients are 
first roasted to a red heat, to expel moisture 
and carbonic acid (from carbonate of soda, 
which is thus reduced to caus¬ 
tic soda—the alkalies can 
only be used in their caustic 
state in the manufacture of 
glass and soap). After being 
roasted, the materials are 
ground up together. The 

glass pots, or retorts, are then put into a furnace, (Fig. 73,) 
which has as many doors, d, as the number of retorts, r, it is 
capable of heating. In Fig. 74, the retorts are seen in their 
position, on a platform around a central grate, through which 
the heat and flame from the furnace enter. When melted, 


Fig. 74. 




209. What is the composition of glass ? Why is lead added to glass man- 























160 ELEMENTS OF CHEMISTRY. 

the glass is taken out on hollow iron rods, to which it readily 
adheres, and it is then blown by the workman into decanters, 
bottles, and other articles, or is poured on a table to form sheet 
or plate glass. When cold enough to handle, the glass is 
carried to an oven, where it is again heated. It is then taken 
to the annealing oven, (Fig. 75.) One end of this oven (the 
* most distant in this fig- 

Fig. 75. ure,) is kept at a high 

heat, and the glass ves¬ 
sels are placed on sliding 
pans, which are covered 
with sand. These pans 
are drawn along from 
time to time by sim¬ 
ple machinery, consisting 
chiefly of a crank, rollers, 
1 Til f and an endless chain. 

When the glass vessels 
reach the cool end of the oven, which generally takes place in 
from one to two days, or even longer, they are annealed, and 
by this process rendered much less brittle, and less liable to 
crack by sudden changes of temperature. When the anneal¬ 
ing oven is full, as fast as one pan is removed at the cool end 
of the oven, another is introduced at the same time at the end 
which"is kept at a high heat. In making the large circular 
tables of crown glass, a globular flask of great size is first pro¬ 
duced, and to this a rapid rotary motion is given, until, by cen¬ 
trifugal force, the whole is suddenly made to assume the form 
of a disc. Tubes are made by drawing out a hollow cylinder of 
partially melted glass.( 114 ) 

210. When carbonate of soda is mixed with an acid, the 
carbonic acid'is driven off with effervescence. Hence this salt 
is used in the manufacture of soda-icater. Common bottled 
soda, is made by dropping into a bottle, about two thirds full 
of water, a crystal of carbonate of soda, and another of tartaric 
acid. The bottle is then tightly corked, and the cork tied 
down. The crystals will gradually dissolve and decompose 
each other. Carbonic acid rises, and is absorbed by the water, 
and, when the bottle is afterwards uncorked, the carbonated 
water flows out with effervescence.* 

* Soda-water is now generally bottled at soda-water fountains under great 
pressure. The various sirups are put in first, and the soda added. 




ganese 1 What other substance is sometimes employed ? Explain the process 
of making glass. 

210. How is common bottled soda-water made ? Explain Fig. 76. How 











THE ELEMENTS AND THEIR COMBINATIONS. 


161 


Fig. 76. 


Fig. 76, represents the method of making soda-water in the 
large way. A is a small strong cask with a funnel at the 
top, and two pipes at the sides, 
all fitting air-tight, and furnished 
with stop-cocks, F, r, r. The 
pipes enter the vessels E and C 
on each side of A, and extend 
nearly to the bottom of those ves¬ 
sels. E and C are also furnished 
with funnels extended beneath the 
liquid which they contain. The 
pipes, B D, proceed upwards to 
the jets, H and L. The two 
sides of the apparatus are similar, 
and may be employed for foun¬ 
tains of two different liquids. 

If soda-water alone is desired, the 
apparatus on one side is all that 
is necessary, but in connection 
with this, a fountain of ginger-beer, or some other drinks may 
be employed. 

The action is as follows : Two or three pounds of chalk, (car¬ 
bonate of lime,) are put into A, and a gallon of water added. 
C and E are also half filled with water, either pure or fla¬ 
vored with sugar, ginger, lemons, &c. The cocks, r, r, are now 
opened, the others being closed. Sulphuric acid is added 
through the funnel F : 

CaO, C0 2 = carbonate of lime. 

SO 3 = sulphuric acid. 

Bring - down CaO, and there is produced 

CaO, S0 3 ^sulphate of lime, insoluble salt. 

[precipitates in the cask A.] 

C0 2 = Carbonic acid. 

[escapes in gas.] 



The carbonic acid, being expelled from the chalk in A, 
passes into the water of C and E, where it is absorbed, and, 
after the absorption has taken place, accumulates in the upper 
part of C and E ; here it exerts a pressure, which, when the 
valves I and S are opened, drives the water up the tubes B 
and D, and out at the jets L and H. 

The gas generator, A, is often fixed upon an axis by which 
it may be made to revolve, and thus the action of the acid on 


is soda-water prepared by this arrrangement ? Explain the diagram. Is the 
water which is drawn from H and L soda, or merely carbonated water? 




















162 


ELEMENTS OF CHEMISTRY. 


the chalk is promoted. The containing vessels are generally- 
made of wood or earthenware, as sulphuric acid dissolves iron 
and zinc rapidly, and carbonic acid acts readily upon copper. 
The tubes are apt to break at the joints ; to remedy this, they 
should be made of pewter or tin; lead also is sometimes used, 
but water standing in contact with lead, frequently acquires 
poisonous properties, by a slight corrosion of the lead. 

When the apparatus is fully charged with carbonic acid, no 
more will be formed in A. Thusj there is no waste of mate¬ 
rials employed in generating the gas. The pressure of the 
gas, however, is frequently so great as to burst the apparatus, 
and fatal accidents have occurred in this way. 

211. Bicarbonate of soda , JNTaO, C0 2 +H0, C0 2 . From 
this symbol it appears, that the bicarbonate of soda consists of 
the carbonate of soda (NaO, C0 2 ), and carbonated water 
(HO, C0 2 ). It is prepared by passing carbonic acid gas into 
a cold solution of the neutal carbonate of soda, or by placing the 
crystals in an atmosphere of carbonic acid, which they rapidly 
absorb. The carbonic acid given off in certain localities is 
sometimes used for this purpose. The ten equivalents of water 
of crystallization (10 HO), which the crystals of carbonate of 
soda contain, they, to a great extent, lose in being converted 
into the bicarbonate. 

Bicarbonate of soda is a white, crystalline powder, which, 
in solution, loses carbonic acid slowly at the temperature of the 
air, and rapidly above 160°. By this decomposition, it passes 
first into a sesquicarbonate, and finally iuto a neutral carbonate. 
At 60° it requires 10 parts of water for its solution, which is 
feebly alkaline to test-paper, and has a milder taste than that 
of the simple carbonate; it is, therefore, more frequently em¬ 
ployed in medicine (199). 

212. Chloride of sodium , common salt , NaCl. The earth 
and sea abound in common salt. In many places it is found 
in solid beds, or irregular strata, of immense thickness. The 
salt of these beds resembles transparent stone, and is therefore 
called rock-salt. It is almost always too impure for use; 
hence, if no natural brine-spring exists in these beds, an arti¬ 
ficial one is formed by sinking a shaft into the rock-salt, and, 
if necessary, introducing water. This, when saturated, is 
pumped up and evaporated, more or less rapidly, in large iron 
pans. As the salt*separates, it is removed from the bottom by 


211. Write and explain the symbol for bicarbonate of soda. How is this salt 
prepared ? State some of its properties. 

212. Write and explain the symbol of the chloride of sodium. How 
much sodium does common salt contain ?—how mnch chlorine? What are 



THE ELEMENTS AND THEIR COMBINATIONS. 


163 


means of a scoop, pressed, while, still moist, into moulds, and 
then transferred to the drying-stove. When large crystals are 
required, as for coarse bay-salt , used in curing provisions, the 
evaporation is slowly conducted. This kind of salt is usually 
obtained from sea-water ; a pound of sea-water contains from 
one half to five eighths of an ounce of common salt. This salt 
has a slightly bitter taste, owing to the presence of salts of 
magnesia. 

As the natural salt-springs contain much more water than 
is necessary for the solution of the salt, a cheaper method of 
evaporation than that by fire is sometimes employed. The 
salt water is pumped up to the top of a lofty scaffolding, filled 
up with fagots, and from this height is made to fall by drops 
through the fagots. It diffuses itself over the branches, and 
thus presents a very large surface to the air passing through 
them. A rapid evaporation is in this way obtained. Upon 
the branches gypsum is first deposited, for this is contained in 
all natural waters, and, being soluble only in a very large 
quantity of water, it is deposited when the water is consider¬ 
ably diminished by evaporation. It forms a hard crust upon 
the branches. When the greater portion of the water is evap¬ 
orated, the concentrated brine is boiled down in large pans, 
with constant stirring, and the granular salt which separates 
is raked out and dried. 

When pure, chloride of sodium is not deliquescent in mod¬ 
erately dry air. It crystallizes in anhydrous cubes (Fig. 77,) 
which are often grouped together 
in pyramids or steps. It requires 
about 2% parts of water at 60°, 
for solution, and its solubility is 
not sensibly increased by heat. 

In alcohol it is insoluble. By 
this property, therefore, it may 
be separated from carbonate of 
soda. At a bright red heat it 
fuses, and is volatile at a still 
higher temperature. 

We find common salt nearly everywhere in nature, because it is indis¬ 
pensable to the life of animals and plants. After storms at sea, the 
leaves of plants in the direction of the wind become covered with salt, 
to the distanee of twenty or thirty miles inland. Even in calm weather 
the air hanging over the sea always contains a minute portion of this 


Fig. 77. 



□dung t>e 


some of the more abundant sources of common salt ? By what process is the 
salt prepared ? Explain Fig. 77. Why is common salt so universally diffused 
in nature ? 









164 


ELEMENTS OF CHEMISTKY. 


substance, which is carried away by every breeze, and deposited on the 
land with the rain. With salt (chloride of sodium) the chlorides of potas¬ 
sium and magnesium, and the sulphates of soda and of lime are derived 
from the sea, and borne by the wind over the land. Immense quantities 
of these salts are, therefore, in time deposited upon the land in the vicin¬ 
ity of the sea, in some cases to such an excess as to have a sterilizing 
effect on the soil. 

But except in the vicinity of the sea, of salt-springs, or beds of salt, this 
substance exists in exceedingly small quantity, and in many places has 
been washed away by rains, or exhausted from the soil by cultivation. 
In such cases the growth of plants is promoted by adding it to the soil. 
When added in excess, salt is a deadly poison to plants. Being soluble, 
it is absorbed by the roots until these decay and crumble into powder. 
Even the most vigorous plants'will soon perish if watered with a strongly 
saline solution. It causes the stems of young plants to assume the ap¬ 
pearance of old wood, the leaves to become brown, first at the point, 
then round at the edge, and afterwards throughout. 

Salt is necessary in the animal system, for without it no complete di¬ 
gestion of food can take place. The following analysis is that of the 
blood of a man while taking his usual diet, and when consuming 154 grains 
of salt daily: 

Daring During 

usual diet. salt diet. 

Water.779-9.767-6. 

Blood corpuscles.130-1.143-0. 

Albumen .. 77-4. 74-0. 

Fibrine. 21. 2-3. 

Fatty matter. IT. 1*3. 

Extractive and salt. 9*3... 118. 


It is, therefore, evident that a salt diet increases the solid constituents 
of the blood, at the expense, in part, of the albumen of the food, and that 
of the blood itself. 

In experiments on the effect of salt in fattening cattle, it has been 
shown that it does not increase their growth as much as is usually sup¬ 
posed, but that it improves their appearance and condition. When 
cattle were deprived of salt for eleven months they appeared sluggish 
and languid, their coats became rough, devoid of gloss and partially bare, 
while those which had been fed with salt were lively, and had a fine, 
glossy coat. 

Soda may be substituted for potash, and, in general, the alkalies may 
be substituted for each other in agriculture. But it is not so with the 
acids which accompany these bases. Sulphuric acid, for example, can¬ 
not be made to do the work of phosphoric acid. Even in regard to the 
alkalies, it is probable that plants are not perfectly indifferent, for saline 
plants seek the sea-shore, or the vicinity of salt-beds, or salt-springs, while 
potash plants prefer the interior. 


213. Nitrate of soda. NaO, N0 5 , occurs native, and in 
enormous quantity, at Atacama, in Peru, where it forms a reg¬ 
ular bed of more than 100 square leagues, covered with clay 
and alluvial matter. Its crystals are deliquescent, and very 


213. Write and explain the symbol of nitrate of soda. Whence is this salt 















THE ELEMENTS AND THEIR COMBINATIONS. 165 

soluble in water. It is employed in making nitric acid. It 
has been substituted for nitrate of potash (saltpetre), in the 
manufacture of gunpowder, but the powder thus made burns 
too slowly, and becomes damp in the air. It was formerly 
used to a considerable extent in agriculture, as a manure, but 
has been discontinued because it tends to render the stalk of 
corn , too weak, and to produce mildew. These faults may, 
however, be corrected by mixing with the nitrate a moderate 
quantity of common salt. 

Ammonium, com. num. 18. symbol NH 4 . 

214. All attempts to isolate this substance have failed, ap¬ 
parently from its tendency to separate into ammonia and hy¬ 
drogen gas. Thus, when ammonical amalgam is made by the 
action of the galvanic current, it soon decomposes into fluid 
mercury, ammonia, and hydrogen. The formation of this 
amalgam from the salts of ammonia, seems to prove that they 
have a metallic base, although the exact nature of that base 
is as yet undetermined. The best evidence we have of the ex¬ 
istence of the metal ammonium, is the perfect comparison 
which its salts bear with those of the alkaline metals. The 
symbol of ammonium is supposed to be NH 4 , because am¬ 
monical amalgam is decomposed into ammonia (NH 3 ), hydro¬ 
gen (H,) and metallic mercury. 

215. Carbonate of ammonia , NH 3 CO ? +HO, or NH 4 0, 
CO„ ( 11B ) carbonate of the oxide of ammonium. The carbon¬ 
ate of ammonia has many of the properties of its base. Al¬ 
though chemically combined with carbonic acid, it still emits 
a pungent odor, and affords an alkaline or basic reaction. 
Exposed to the air, at common temperatures, it disengages 
ammonia, loses its pungency, and crumbles down to a soft 
white powder, which is a bicarbonate of ammonia. The 
properties of this bicarbonate and those of potash (199.), and 
soda (211.), are much milder than those of the carbonates of 
these bases. When thrown on a hot iron, carbonate of am¬ 
monia evaporates without melting. 

Carbonate of ammonia is the form in which ammonia is 


obtained ? What are some of its properties ? Why can it not be substituted 
for saltpetre in the manufacture of gunpowder ? What effect do the nitrates 
of soda and potash produce when applied to the soil ? 

214. Write the combining number and symbol of ammonium. Why have 

all attempts to isolate the metal ammonium failed ? What is the best evidence 
of the existence of this metal ? . TT , 

215. Write and explain the symbol of carbonate of ammonia. How mueh 
carbon, hydrogen, nitrogen, and oxygen are contained in this salt ?—how much 
carbonic acid ? State some of its properties. What is said of the properties 




166 


ELEMENTS OF CHEMISTRY. 


found in the atmosphere. It is derived from the decay of 
animal and vegetable ^substances, which produces at the same 
time ammonia and carbonic acid. It is the chief fertilizing 
substance of common manures, and produces the odor which 
arises from stables and manure heaps, This may be removed 
by sulphuric or hydrochloric acid, which unite with the am¬ 
monia, expelling the carbonic acid, and forms sulphate of am¬ 
monia, or chloride of ammonium. This salt is used in medi¬ 
cine as a stimulant, and, mixed with lime, is frequently em¬ 
ployed, under the name of “smelling salts,” as a restorative 
from faintness. It is the chief fertilizing substance produced 
by the decay of animal and vegetable substances, which con¬ 
tain nitrogen. The odor of stables and manure-heaps is owing 
to the production of carbonate of ammonia. This may be re¬ 
moved by a bowl of sulphuric or muriatic acid, which unites 
with the ammonia, forming sulphate of ammonia or chloride 
of ammonium. 

216. Chloride of ammonium, sal ammoniac , NH 4 Cl, or 
NH 3 HC1, (liydrochlorate of ammonia .) Sal ammoniac is 
largely manufactured from the ammoniacal liquid of gas works, 
and from the distillation of bones, and other animal refuse, in 
the preparation of animal charcoal. The impure and highly 
offensive solutions thus obtained, are treated with a slight ex¬ 
cess of hydrochloric acid, by which the free alkali is neutralized, 
and the carbonate and sulphate of ammonia decomposed with 
the evolution of carbonic acid and sulphuretted hydrogen. The 
free ammonia of these solutions, and that contained in the de¬ 
composed carbonate and sulphuret, form chloride of ammonium 
in the solution. This liquid is evaporated to dryness, and the 
salt carefully heated to expel and decompose the tarry matter ; 
it is then purified by sublimation in large iron vessels lined 
with clay, and surmounted with domes of lead. 

Chloride of ammonium is found native in Italy, and in 
several other places. When sublimed it has a fibrous texture. 
It is tough and difficult to powder. When crystallized from 
water it separates, under favorable circumstances, in distinct 
cubes, or octahedrons, but the crystals are usually small and 
aggregated together. If a slip of glass is washed over with a 
hot saturated solution of sal ammoniac, the moisture will al¬ 
most immediately be evaporated, and the salt will be deposited 


of the bicarbonate of ammonia ? Mention some of the uses of carbonate of am¬ 
monia ? 

216. Write and explain the symbol of chloride of ammonium. How is sal 
ammoniac manufactured ? Where is this salt found native ? What are some 
of its properties ? For what purpose is sal ammcfniac used ? 



THE ELEMENTS AND THEIR. COMBINATIONS. 


167 


in a beautifully arborescent form. The same method may 
often be employed with advantage in crystallizing other sub¬ 
stances^ 116 ) If a glass window is painted with a hot saturated 
solution of sal ammoniac, the salt will be deposited in a very 
beautiful radiated form, and wdll admit the light without being 
transparent. For rendering windows semi-opaque, this method 
is much preferable to the common way of using paint, paste, 
and similar materials. 

Sal ammoniac is used in tinning iron and copper. These 
metals are rubbed over with the solution, or dipped into it to 
prevent the oxidation of their surfaces. In soldering metals it 
answers a similar purpose. In dyeing it is used to fix, brighten, 
and modify the colors. It is largely employed in medicine, and 
is used both internally and externally. 

217. Sulphide of ammonium , NH 4 S, or NH 3 , HS, (Jiy- 
drosutyihuret of ammonia,) is formed by passing sulphuretted 
hydrogen through liquor of ammonia to complete saturation. 
When saturated, it will no longer cause a precipitate in a solu¬ 
tion of sulphate of magnesia. The hydrosulphuret of ammonia 
thus obtained must be kept in well-closed bottles, since it is de¬ 
composed by contact with the atmosphere. A yellow sul- 
phuret of ammonium is in this case formed. It is invaluable as 
a reagent in the laboratory (195.), and is also used in medicine. 

218. Nitrate of ammonia, N H 3 ,N0 5 +HO, or NH 4 0, N0 5 , 
(nitrate of the oxide of ammonium ,) is easily prepared by ad¬ 
ding carbonate of ammonia to slightly diluted nitric acid, until 
neutralization has been reached. The carbonic acid of the car¬ 
bonate of ammonia is expelled, and nitrate of ammonia formed 
by the union of the nitric acid with the ammonia. By slow 
evaporation, at moderate temperatures, it crystallizes in six- 
sided prisms, like those of nitrate of potash (Fig. 71.) It dis¬ 
solves in two parts of water, and is feebly deliquescent. Like 
the other nitrates, it deflagrates on contact with heated com¬ 
bustible matter. Its chief use in the laboratory is in making 
nitrous oxide gas (167.) 

219. The ammoniacal salts are easily known. They are all 
decomposed or volatilized at a high temperature, and, when 
heated, with hydrate of lime, or solutions of caustic potash or 
soda, they evolve ammonia, which may be known by its odor 


217. Write the symbol of sulphide of ammonium ;—of hydrosulphuret of am¬ 
monia. State the process by which it is prepared. How much nitrogen, hy¬ 
drogen, oxygen, and nitric acid does nitrate of ammonia contain ? 

218. Write and explain the symbol of nitrate of ammonia. How is this salt 
prepared? State some of its properties. 

219. How are the ammoniacal salts detected ? Mention the peculiar prop¬ 
erties of the alkaline metals as given in art. 202. 




168 


ELEMENTS OF CHEMISTRY. 


and its alkaline reaction. The salts of ammonia are more or 
less soluble* Tartaric acid and chloride of platinum give the 
same reaction in amrrroniacal solutions as in those of potash, 
but the former are easily distinguished from the latter, as they 
volatilize (not only the ammonia , but the whole salt) on the 
application of heat. 


METALS OF THE ALKALINE EARTHS. 

Barium, 2-{-. 69. Ba. 

220. Barium is procured by heating baryta in an iron tube, 
through which the vapor of potassium is conveyed. The vapor 
of potassium takes the oxygen from the baryta, and the metal 
barium is reduced. The reduced metal is extracted by quick¬ 
silver. Barium has the color and lustre of silver. It is ductile, 
and may be beaten flat, though with difficulty. Like potassium 
and sodium it decomposes water with great energy. 

221. Protoxide of barium , baryta , BaO. This oxide has 
an exceedingly strong affinity for water, and, when mixed 
with it, slakes like lime, though with a more intense heat; 
this is so great as sometimes to cause the baryta to appear ig¬ 
nited. The hydrate is a white, soft powder, having a great 
attraction for carbonic acid, and soluble in 20 parts of cold and 
3 of boiling water. A hot saturated solution deposits crystals 
on cooling. The formula for these is BaO, HO + 9HO, (1 equiva¬ 
lent of the water of composition and 9 of the water of crys¬ 
tallization.) Solution of hydrate of baryta is a valuable re¬ 
agent. It is highly alkaline to test-paper, and is instantly 
rendered turbid by the smallest trace of carbonic acid. 

222. Sulphate of baryta , heavy spar , BaO, S0 3 , is found 
native in beautiful crystals, sometimes tabular, and sometimes 
prismatic. It occurs in considerable quantity in trap and other 
igneous rocks, forming often veins of several feet in thickness 


220. Write the specific gravity, combining number, and symbol of barium. 
How is this metal procured ? State some of its properties. 

221. Write the symbol of the protoxide of barium. What are some of the 
properties of this oxide 1 Mention some of the properties of the hydrate. 
Write and explain the formula for the hydrate. In this formula why are not 
HO and 9HO united ? What is the principal use of hydrate of baryta ? 

222. Write and explain the symbol of sulphate of baryta. How does this 
salt occur in nature '! For what pui-pose is it employed ? Why is the natural 
sulphate called heavy-spar ? State some of the properties of this salt. 




THE ELEMENTS AND THEIR COMBINATIONS. 169 

and miles in extent. It is mined for mixing with white paint, 
tor this purpose it is ground to powder, and this is washed 
with dilute sulphuric acid, by which more or less of oxide of 
iron is dissolved out, and its color thus improved. The natural 
sulphate is called heavy spar , on account of its great weight, 
which is often as high as 4 4 or 4*8 (sp. gr.) 

Sulphate of baryta is not sensibly soluble in water,^ or in 
any dilute acid. Hot sulphuric acid dissolves a little, but the 
greater part separates again on cooling. On account of the 
great insolubility of this salt, it is not poisonous. 

223. Solutions of salts of barium are constantly kept in the 
laboratory as chemical tests. The nitrate and chloride are 
used to precipitate sulphuric acid from its solution. The hy¬ 
drate of baryta is used to effect the separation of the alkalies 
from the other bases, whieh it does by its greater affinity for 
these bases. It is also used to separate carbonic acid from 
certain gaseous mixture. The soluble salts of baryta are 
poisonous. 

Strontium, 2-f-. 44. Sr. 

224. Strontium may be obtained from its oxide by means 
similar to those employed in procuring barium. It is a silver- 
white metal, with less lustre than barium. It is ductile, and 
decomposes water at common temperatures, and oxidizes 
rapidly in the air. 

225. Protoxide of strontium , strontia , SrO. This oxide 
resembles in every respect the protoxide of barium, or baryta. 
Like that substance, it slakes with a great elevation of tem¬ 
perature when mixed with water. It is less caustic than 
potash, soda, or baryta. A hot saturated solution on cooling 
deposits crystals which contain 10 eq. of water. The hydrate 
has a strong attraction for carbonic acid. 

226. Nitrate of strontia, SrO, N0 5 , crystallizes in anhy¬ 
drous octahedrons, which are transparent and colorless. They 
require for solution 5 parts of cold and 1 part of boiling 
water. They deflagrate slightly on charcoal, and give a red 
flame. 

m 

* This salt requires for its solution 43,000 parts of cold water. It is not much 
more soluble in hot or acidulated water. 


223. For what purpose ar^the solutions of salts of baryta employed in the 
laboratory ? What salts of baryta are poisonous ? 

224. Write the specific gravity, combining number, and symbol of strontium. 
How may this metal be obtained ? State some of its properties. 

226. Write the symbol of nitrate of strontia. How much strontium does ni¬ 
trate of strontia contain?—how much strontia?—how much oxygen?—how 
much nitrogen ?—how much nitric acid ? State some of the properties of ni- 

8 



170 


ELEMENTS OF CHEMISTRY. 


The salts of strontia, which are soluble, give a fine rose-red, 
or crimson color to the flame of burning bodies. For this 
purpose they are used in theatrical exhibitions, and in fire¬ 
works. They are detected by the crimson flame which they 
give to burning alcohol. 

Calcium, 2-f. 20. Ca. 

227. Calcium is a silver-white metal, solid at the ordinary 
temperatures. It oxidizes rapidly in the air, and inflames 
when heated. It decomposes water. 

Protoxide of calcium , limey CaO. Lime is obtained by ig¬ 
niting chalk or other kinds of limestone. If a piece of chalk 
be exposed to the blowpipe flame, it will become much lighter, 
and will no longer effervesce with acids. It has lost its car¬ 
bonic acid, and is now lime. If a portion of it be placed on 
moistened red litmus-paper, it causes blue spots ; it has, there¬ 
fore, an alkaline reaction, which the chalk had not. 

To obtain lime absolutely pure, it must be made by igniting 
to whiteness, in a platinum crucible, an artificial carbonate of 
lime, procured by precipitation from nitrate of lime, by carbon¬ 
ate of ammonia : 

CaO, NO s = nitrate of lime. 

NH 3 , C0 2 = carbonate of ammonia. 

By double exchange. 

CaO, C0 2 — carbonate of lime, insoluble salt. 

[precipitated from solution.} 

NH 3 , NO s =nitrate of ammonia, soluble salt. 

[remains in solution.] 

Pure lime is a brittle, white, earthy solid, often of considera¬ 
ble hardness. It is quite infusible, and phosphoresces or emits 
a pale white light at a high temperature. When moistened 
with water it slakes with great violence, evolving heat, and 
crumbling to a soft, white, bulky powder, which is a hydrate 
containing a single equivalent of water. The latter can be 
again expelled by a red heat. When slaked, even with ice, 
lime is raised to a temperature of 212°, and the steam, as it 
xses, carries with it a large quantity of lime in a state of 
minute division. When exposed to the air, it also falls into 


trate of strontia. For what purpose are the salts of strontia sometimes em¬ 
ployed ? How are the salts of strontia detected ? 

327. Write the specific gravity, combining number, and symbol of calcium. 
Mention .some of the properties of this metal. Write the symbol of lime. How 
is lime obtained? How is it prepared in a state of absolute purity ? Write 
out and explain the diagram. State some of the properties of lime;—lime- 
water. In what respects does lime resemble strontia and baryta ? For what is 



THE ELEMENTS AND THEIR COMBINATIONS. 


171 


powder, in consequence of absorbing moisture from the atmos¬ 
phere. The hydrate is soluble in water, though far less so 
than either the hydrate of baryta or of strontia. Warm water 
dissolves less lime than cold water. 

Hydrate of lime has been obtained in thin, delicate crystals, 
which are transparent, regular, six-sided prisms. These are 
formed by evaporation under the receiver of the air-pump, or 
by placing a vessel containing lime-water, and another con¬ 
taining sulphuric acid, under a glass jar. The sulphuric acid 
absorbs the moisture from the air above the lime-water, and 
thus hastens its evaporation. The acid is renewed as often as 
it becomes saturated with moisture. t 

Lime-water has a strong alkaline reaction, a nauseous taste, 
and, when exposed to the air, becomes instantly covered with 
a pellicle of carbonate, by absorption of carbonic acid from the 
air. It must, therefore, be kept in closely-stopped vessels. It 
is used, like baryta-water, as a test for carbonic acid. It is 
also of great use in medicine. 

When slaked and made into mortar, lime gradually absorbs 
carbonic acid from the atmosphere, and is converted into car¬ 
bonate of lime, or limestone ; but a great length of time 
usually elapses before this conversion is complete. Under 
favorable circumstances, mortar acquires extreme hardness 
with age. Lime cements, which resist the action of water, 
contain clay. A water cement may be made by burning an 
intimate mixture of chalk with one-fifth clay. When this is 
ground to powder and mixed with water, solidification speedily 
ensues, and the cement in this condition is unaffected by water. 

228. The application of lime in certain circumstances is of 
great service to plants. It is beneficial, (1.) where the soil 
does not already contain a supply ; (2.) where such plants as 
peas, clover, tobacco, &c., (called lime plants, from the quan¬ 
tity of lime which they contain) are to be cultivated ; (3.) on 
clay soils, which lime tends to loosen, and render less adhesive, 
and also to set free the alkalies which such soils contain. Lime 
should not be added, (1.) on light, dry and shallow soils, 
which are deficient in vegetable matter; (2.) on fermenting 
barn-yard manure, as the addition of lime expels the ammonia, 
the chief fertilizing element in such manure ; (3.) in all cases 
where lime is applied to the soil, the chief precaution is not to 
add it in excess. 


lime-water used ? Why does mortar harden with age ? What do lime ce¬ 
ments that harden under water contain ? When may lime be applied to plants ? 
Where should not lime be added 1 Why does hard water decompose soap ? 
What are the principal parts of the Drummond light? (135 and 183.) 




172 


ELEMENTS OF CHEMISTRY. 


In the following table the amount of lime removed in the tops, straw, 
and grain of various crops, is shown. The crops were obtained from an 
acre of land: 


Wheat... .25 bushels. Lime.. 8‘Y lbs. 

Barley.... 38 “ . “ 15-0“ 

Oats.50 “ . “ 8-2 “ 

Turnips...25 tons. “ 138-8 “ 

Potatoes .. 9 “ “ 266-0 “ 

Red clover. 2 “ “ 126‘0 “ 


Lime combined with phosphoric acid forms the skeletons 
of the higher order of animals, and, in combination chiefly 
\yith carbonic acid, the shells of the lower animals. Animals 
obtain it from the plants on which they feed. 

The caustic properties of lime render it serviceable in tan¬ 
ning. Skins soaked a few days in lime-water, are easily freed 
from their hair ; they are then thrown into a tan-pit. 

Lime is generally found in spring and well-water ; hence 
these waters are called hard , because lime decomposes the 
soap, taking its acid,* and setting free the fatty matter of the 
soap. 

When ignited, lime gives out an intense light, and hence, 
in the Drummond light , a mixed stream of oxygen and hy¬ 
drogen (p. 127,) is made to fall on a cylinder of lime. This 
cylinder revolves slowly, so that it consumes more equally by 
the flame of oxygen and hydrogen. 

229. Chloride of calcium, CaCl, is usually prepared by dis¬ 
solving marble in hydrochloric acid, or as a by-product in sev¬ 
eral chemical manufactures. The salt separates from a strong 
solution in regular, six-sided prisms, which are colorless, and 
exceedingly deliquescent. If a little of the solution be dried 
by heat on a glass plate, and allowed to stand a few minutes 
in a cool place, the-thin film of salt will deliquesce to such an 
extent as to be nearly liquid on the plate. These crystals con¬ 
tain six equivalents of water. By heat the water is expelled, 
and by a temperature of strong ignition the salt is fused. 

Anhydrous chloride of calcium dissolves in water with the 
evolution of heat; but the crystallized salt produces cold by 
solution. In forming freezing mixtures, the crystals are re¬ 
duced to powder, and mixed with snow or powdered ice. In 
a fused condition the chloride is of great use in drying gases, 
for which purpose the gases are passed slowly through tubes 

* This will be explained more fully hereafter. 


229. Write the symbol of the chloride of calcium. How is this substance 
usually prepared ? State some of its properties. Explain Fig-. 78. 










THE ELEMENTS AND THEIR COMBINATIONS. 


173 


filled with fragments of the salt. A 
tube thus prepared is represented in 
Fio\ 78. Chloride of calcium is freely 


Fig. 78. 




soluble in alcohol, and forms with anhydrous alcohol a crystal- 
lizable compound. 

230. Sulphate of lime, gypsum, selenite, CaO, S0 3 . Na¬ 
tive sulphate of lime in a crystalline state, containing 2 eq. 
oi water, is found in considerable abundance in some localities. 
When melted it is rendered anhydrous. It is often associated 
with rock-salt, and is sometimes met with in the anhydrous 
state. When regularly crystallized, it is termed selenite. In 
a pure state it may be obtained from a moderately concentrated 
solution of chloride of calcium, by precipitation with sulphuric 
acid. It is soluble in about 500 parts of cold water, and its 
solubility is a little increased by heat; it is precipitated from 
its solution by alcohol. When a large quantity of sulphuric 
acid is poured upon a mass of quicklime, the whole becomes 
red hot. 

Gypsum is largely employed in making casts of statues and 
medals, and also for moulds in porcelain and earthenware 
manufactures, and for other applications. It is exposed to 
heat in an oven when the temperature does not exceed 260°, 
and when the water of crystallization is thus expelled, it is 
reduced to a fine powder. When this powder is mixed with 
water, it solidifies after a short time, forming again the hy¬ 
drate. If, however, the gypsum has been overheated, this ef¬ 
fect does not take place. Artificial colored marbles are fre¬ 
quently prepared by inserting pieces of natural stone in a soft 
stucco of this substance, and polishing the surface when the 
cement has become hard. Sulphate of lime is one of the most 
common impurities of spring water (p. 163). 

Gypsum has been long and extensively ‘applied to the land 
as a manure. It is especially useful to leguminous plants, as 
beans, peas, &c. (p. 171.) These plants not only absorb the 
lime, but. also the sulphur of the sulphuric acid. Gypsum has 
also a beneficial effect on the growth of plants, as it fixes in 
the soil the carbonate of ammonia contained in the air and in 
rain-water. This effect is produced by a double exchange,— 
the sulphate of lime and carbonate of ammonia becoming car¬ 
bonate of lime and sulphate of ammonia. During drought it 


23 J. Write the symbol of sulphate of lime. What is the principal source of 
sulphate of lime 1 Mention some of its properties. How is it prepared in a 
pure state ? For what purposes is gypsum used ? In what respects is it use¬ 
ful as a manure ? 







174 


ELEMENTS OF CHEMISTRY. 


sustains plants by its power of attracting moisture from the 
atmosphere. 

231. Carbonate of lime, chalk, limestone, marble, CaO, C0 3 . 
Carbonate of lime forms rocky beds of immense extent and 
thickness in almost every part of the world. It is freely taken 
up by water which contains carbonic acid, although not sensi¬ 
bly soluble in pure water (p. 102). Almost all natural waters, 
therefore, contain this substance dissolved by the carbonic acid, 
which is always present in these waters. This is particularly 
the case in limestone districts. Boilers in which such water 
is heated, speedily become lined with a thick incrustation of 
carbonate of lime. The crystals of carbonate of lime have a 
greater variety of form and aspect than those of any other 
substance, except perhaps the crystals of snow. 

Marl is a mixture of carbonate of lime (generally derived from shells 
or other organic remains) with clay in various proportions, and in dif¬ 
ferent degrees of compactness. Some marls contain but little clay and 
a large quantity of sand ; these are sometimes called sandy marls. Other 
varieties contain a large proportion of loam, and are therefore called 
loamy marls. Where the proportion of clay is small, the marl has 
nearly the same action upon the soil as lime. Where clay is the princi¬ 
pal ingredient, it acts in the soil partly as lime, but its properties and 
action resemble more those of clay soils (252). Hence, all sandy soils are 
improved by marls, while argillaceous marls, applied to clay lands, are 
of little or no use. A larger surface of the cropped soil of Europe is im¬ 
proved by means of calcareous marls and sands, than by farm-yard man¬ 
ure and burned lime. 

Lithographic stones are made of a fine compact limestone. 
They are covered with wax, grease, or varnish, and through 
this coating the design is traced. A weak solution of nitric 
acid is afterwards applied to the stone, and the lime dissolves 
in those places which are unprotected ; the other places ac¬ 
cordingly remain raised, and, when the wax is dissolved off, 
the design may be transferred by the press as from other 
plates. 

232. j Fluoride of calcium, fiuor spar, CaF, occurs beauti¬ 
fully crystallized in various colors, in lead veins, the crystals 
having commonly the cubic, but sometime? the octahedral 
form. They always cleave parallel to the faces of an octahe¬ 
dron. A small portion of the earth of bones (a few thousandths,) 
consists of fluoride of calcium ; a somewhat larger proportion 


231. Write the symbol of carbonate of lime. How does carbonate of lime 
occur ? What is said of the solubility of carbonate of lime? What is said of 
marl ? Of what are lithographic stones made ? How are engravings made on 
these stones ? 

232. Write the symbol of fluoride of calcium. How does this substance oc- 



THE ELEMENTS AND THEIR COMBINATIONS. 


175 


is found in the enamel of teeth ; and a still larger quantity is 
contained in fossil bones. It is insoluble in pure water, but 
like the other insoluble salts of lime, it is dissolved, to a small 
extent, in water containing carbonic acid. 

Some varieties of fluor spar, when heated, emit a green, 
red, or yellow light. By sulphuric acid it is decomposed with 
evolution of hydrofluoric acid (p. 110). 

233. Chloride of lime , bleaching poivder , CaO, ClO-fCa 
CL* Chloride of lime is formed when chlorine gas is grad¬ 
ually added to lime slightly moist, and kept cool. It is a soft 
white powder, very deliquescent, easily soluble in about 10 
parts of water, giving a highly alkaline solution, which bleaches 
freely. 

The use of chloride of lime, as a disinfectant, depends on the 
action of the carbonic acid of the atmosphere, which gradually 
expels the chlorine gas, and converts the lime into the car¬ 
bonate. After a solution of chloride of lime becomes in this 
way covered with a crust of carbonate, the action entirely 
changes, the chloride of lime gives off pure oxygen, and be¬ 
comes converted into chloride of calcium (OaOl). 

234. Phosphate of lime originally exists in almost all soils, 
but, being appropriated in considerable quantity by most val¬ 
uable plants, it is generally exhausted sooner than any other 
constituent. The analyses of beets, carrots, beans, peas, po¬ 
tatoes, asparagus, cabbage, show phosphate of lime (as well 
as phosphate of magnesia and potash). Indian com, rice, wheat, 
barley, and oats contain a considerable proportion of phos¬ 
phate of lime. It forms also 17 per cent, of the ash of cot¬ 
ton. The cotton crop of the United States for 1849 amounted 
to 527,101 tons. This contained 891 tons of phosphate of lime, 
very little of which was returned to the soil from which it was 
taken. Jdther crops, also, carry off immense quantities of this 
substance. It is also contained in every tree, shrub or plant, 
either cultivated or wild. Hence the great fertilizing effect 
of the application of phosphate of lime to the soil. 

* A mixture of hypochlorite of lime, CaO, CIO, and chloride of calcium. 
Cad- 


cur 1 In what parts of the animal frame is fluoride of calcium found ? What 
is said of its solubility ? What other properties of fluor spar are mentioned ? 

233. Write the .symbol of chloride of lime. How is it formed ? Mention 
©ome of its properties. Upon what does its use as a disinfectant depend ? 
What is the action after the chloride of lime solution becomes covered with a 
crust of carbonate of lime ? 

234. What is said of phosphate of lime? 




176 


ELEMENTS OF CHEMISTRY. 


But in order that phosphate of lime may be appropriated by plants, it 
is necessary that it should be in a soluble form. By grinding it up into 
fin e powder (bone-dust) it is rendered more soluble. But a better 
method, and one now more generally adopted, is to dissolve bones in 
sulphuric acid, which takes part of the base (lime), leaving the phosphoric 
acid combined in excess with the remainder. With this remainder the 



When applied to the soil the acid phosphate immediately finds lime, 
and is converted into the neutral phosphate which being in a state of ex¬ 
ceedingly fine division (as is also the sulphate of lime), is readily dis¬ 
solved in the soil by water containing carbonic acid and ammonia. 
(Hence the necessity, on soils not fertile, of applying organic manures, as 
stable manure, with the super-phosphate of lime, to furnish'by their de¬ 
composition the requisite carbonic acid and ammonia.) In heavy clay 
soils, it is better to apply bones in coarse fragments rather than in fine 
powder, in order to render the soil more friable, at the same time that 
the required phosphate of lime is supplied. In this ease the effect is not 
apparent for two or three years. To hasten the action of the phosphate 
of lime on the soil, the English farmers throw the broken or powdered 
bones into a heap with moist earth, where decomposition speedily com¬ 
mences. 

The phosphate of lime in bones is a mixture of two tribasic phosphates, 
that is, of phosphates in which one equivalent of phosphoric acid is 
united to three equivalents of base. 3CaO, P0 5 is the symbol of one of 
these tribasic phosphates; that is, it consists of phosphoric acid united 
to three equivalents of lime • the second has the symbol 2CaO, HO, PO 5 , 
or phosphoric acid combined with two equivalents of lime, and one of 
basic water. 

235. The soluble salts of lime are instantly detected by ox¬ 
alic acid, or an oxalate in solution, which gives a dense white 
precipitate of oxalate of lime. This is an exceedingly charac¬ 
teristic test. 

Magnesium, 1-f. 13. Mg. 

236. Magnesium is a silver-white metal, with a high lustre, 
not acted on by cold water, which has been previously freed 
from air by boiling. 

Magnesia, calcined magnesia , MgO. Magnesia is a soft, 
white, tasteless substance, which slowly attracts moisture and 
carbonic acid from the atmosphere, and unites quietly with 
water to form the hydrate. In this resppct it differs from the 
hydrate of lime, baryta, and strontia. It possesses a very 
small degree of solubility, and, like lime, is less soluble in hot 
than in cold water, requiring about 50,000 parts of water at 
60°, and 36,000 parts at 212°. 


235. How are the soluble salts of lime detected ? 

236. Write the specific gravity, combining number, and symbol of magne¬ 
sium. Mention some of its properties. Write the symbol of magnesia. State 
some of its properties. 



THE ELEMENTS AND THEIR COMBINATIONS. 177 

237. Sulphate of magnesia, Epsom salt, MgO, S0 3 ,-f-7H0, 
occurs in sea-water, and in the water of many mineral springs. 
It also occurs crystallized in long, slender, prismatic crystals 
(see Fig. 79.), or as an efflorescence on certain rocks and 
soils which contain magnesia, and a sulphate or sulphuret. 
It is now manufactured in large quantities, by acting on 
magnesian limestone, with sulphuric acid, which produces 
a mixture of sulphate of lime and sul¬ 
phate of magnesia. The sulphate of 
magnesia being soluble, is easily re¬ 
moved by filtration from the sulphate 
of lime, which is nearly insoluble 
(230). From a hot saturated solu¬ 
tion, this salt crystallizes beautifully 
in four-sided rectangular prisms. This 
crystallization is represented in Fig. 79. 

This salt may also be crystallized on 
a slip of glass ( ne ). The crystals of sulphate of magnesia are 
soluble in an equal weight of water at 60°, and in a still 
smaller quantity at 212°. They have a nauseous bitter taste. 
It is exceedingly valuable in medicine as a mild and safe 
cathartic. By heat 6 eq. of water are easily driven off, but the 
seventh is firmly retained. 

238. Carbonate of magnesia, MgO, C0 2 , is insoluble in 
water, but, like carbonate of lime, (231.) dissolves in a solution 
of carbonic acid. When stirred up with water, it manifests a 
slight alkaline reaction. When this solution is allowed to 
evaporate spontaneously, small prismatic crystals are deposited, 
which consist of carbonate of magnesia, with 3 eq. of water. 
In dry air they effloresce and lose 2 eq. of water. This salt 
has important uses in medicine. 

239. The salts of magnesia are known by a white crystal¬ 
line precipitate, which they form with the soluble phosphates, 
especially with phosphate of soda, or by the precipitate formed 
with ammonia. Though most plants contain a small propor¬ 
tion of magnesia, yet it is rarely necessary or advisable to add 
any of its salts to the soil, as this usually contains all the mag¬ 
nesia that is requisite. 


237. Write the symbol of sulphate of magnesia. How does this salt occur ? 
How is it now manufactured ? What is the form of its crystals ? Explain 
Fig. 79. State some of the properties of sulphate of magnesia. 

238. Write the symbol of carbonate of magnesia. Where is this salt found ? 
State some of its properties. 

239. How are the salts of magnesia detected ? How are the metals of this 
group distinguished from those of the first group ? (p. 148.) What are the pecu¬ 
liar properties of the metals of this group ? (p. 148 ) 

8* 






178 


ELEMENTS OF CHEMISTRY. 


GROUP THIRD. 

Aluminum, com. num. 14. symbol Al. 

240. Aluminum is obtained in the form of a gray powder, 
resembling finely divided platinum, with shining tin-white 
points scattered among the powder. The whole may be ren¬ 
dered tin-white by burnishing. It may be compressed in an 
agate mortar into larger scales, having the perfect metallic 
lustre. 

241. Alumina , sesquioxide of aluminum, A1 2 0 3 , is pre¬ 
pared by mixing alum (sulphate of alumina and potash) with 
carbonate of ammonia. The sulphuric acid leaves the alumina 
and unites with the ammonia, forming sulphate of ammonia, 
and the carbonic acid is driven of!'. The latter being soluble, 
remains in the solution, while the alumina being insoluble is 
precipitated in an extremely bulky, white, gelatinous precipi¬ 
tate. In this form it is a hydrate of alumina. By remaining 
in the air it dries, and its volume becomes reduced to a few 
hundredths of the bulk of the humid mass. To render it pure, 
the hydrate is washed. It is then dried and ignited to white¬ 
ness. Thus obtained, alumina is white and friable. It has no 
taste, but adheres to the tongue. It is very little acted on by 
acids. When, however, the hydrate is dried in the air, or by 
a gentle heat, without ignition, it dissolves freely in dilute 
acids, and in caustic potash or soda. But if the alumina is 
kept for two days moist, or in the solution in which it was pre¬ 
cipitated, even sulphuric acid will not dissolve it immediately. 

It is highly hygrometic, condensing about 15 per cent, of mois¬ 
ture from the atmosphere in damp weather. It is fusible 
before the oxy-hydrogen blowpipe, into transparent and colorless 
globules, which take a crystalline structure on cooling. 

242. Alumina appears blue in the sapphire, red in the 
oriental ruby, green in the oriental emerald, yellow in the 
oriental topaz, violet in the oriental amethyst, brown in ada¬ 
mantine spar. All these minerals may be considered as varie¬ 
ties of sapphire, of which the composition is pure alumina. 
The colors are due to very small quantities of metallic oxides. 
Emery is a coarse form of alumina, used on account of its ex- _ 
treme hardness in polishing glass and precious stones. Alumina 


240. Write the combining number and symbol of aluminum. State the 
properties of this metal. 

241. Write the symbol of alumina. How is alumina prepared ? What are 
its properties ? 

0 



THE ELEMENTS AND THEIR COMBINATIONS. 


179 


can hardly be ranked among either the bases or the acids. It 
unites with the strong acids without neutralizing them, for the 
salts thus formed have an acid reaction. It also unites with 
potash and other bases, and these salts have a basic or alkaline 
reaction. 

243. Clay is a silicate of alumina. If a piece of clay be 
hollowed out, and some water poured into the cavity, it will 
not percolate through it as it does through sand or lime. 
When beds of clay exist beneath the soil, the rain is unable to 
penetrate through these beds, and consequently bogs and 
marshes are formed. These may be drained by boring holes 
through the clay beds down to a layer of more loose earth, 
through which the water can flow. In many places in the 
interior of the earth, alternate beds of clay and sand are 
formed, one above the other (Fig. 80.) If these strata ascend 


Fig. 80 . 



on each side, forming hills, the rain water, as it runs down, 
must collect between the layers of clay, and rise in them 
wherever an opening exists, or is formed. From the figure it 
is obvious that if a boring is made through a second bed, as at 
b, the water may rise higher than in the boring through the 
first. These artificials fountains are called Artesian wells , 
from the province of Artois, in France, where they were first 
made. 

Clay acquires a violet color, when digested with an infusion 
of logwood for some hours, and renders the solution much more 
transparent. This it does by its power of absorbing coloring 
matter and rendering it insoluble. It also absorbs unctuous 
substances, and hence it is much used for extracting grease- 


243 . What form of alumina is clay ? Mention some of the properties of this 
substance. Explain Fig. 80. What are Artesian wells ? What other proper¬ 
ties of clay are mentioned ? In what rocks is clay an important constituent 1 
Mention the composition of red pottery ware of common white ware. How 














180 


ELEMENTS OF CHEMISTRY. 


spots from wood, paper, &c. It is spread over the surface of 
these substances, and allowed to remain a day or two in con¬ 
tact with them. A soft variety of clay is used in manufac¬ 
tories, for removing the grease applied to wool in spinning. 
That clay has much greater power than sand of imbibing 
moisture, may be shown by placing half an ounce of dry pul¬ 
verized clay on a filter, and half an ounce of sand on a second, 
and pouring water on each. After filtration has ceased, the 
clay will have gained three-eighths of an ounce, and the sand 
only one-eighth of an ounce. If the sand is very coarse, its in¬ 
crease of weight will be still less. 

Granite, porphyry, trachyte, and other unstratified rocks, 
consist in great part of clay, or silicate of alumina. Olay is 
also derived from the decomposition of slate and shale, and 
often from that of other stratified rocks. Decomposed feldspar, 
one of the constituents of granite, forms the clay which is used 
in the manufacture of porcelain. This clay is often colored by 
the oxide of iron. 

The composition of feldspar is— 

KO, Si0 3 4-Al 2 0 3 , SSi 0 3 . 

silicate of potash, silicate of alumina. 

By the action of water containing carbonic acid, the silicate of potash is 
dissolved out, and silicate of alumina, or clay, remains. As the above 
formula indicates, clay is not a mechanical mixture, but a definite chemi¬ 
cal compound. Though the sand and other substances, which are gene¬ 
rally mixed with it, may be separated by washing, yet the fine clay which 
remains will consist of nearly 60 silica to 40 alumina. 

In agriculture, clay is one of the most common, and most important in¬ 
gredients that enter into the composition of soils. Without it, no soil 
will maintain for a length of time its fertility. Though alumina is not a 
constituent of either animals or plants, yet clay is the great agent in the 
soil, which condenses carbonic acid and ammonia from the atmosphere, 
besides performing many other important offices, the nature of which 
cannot as yet be understood, but will be explained more fully hereafter. 
When mixed with the soil, it enables the latter to retain the fertilizing 
substances of manures both liquid and gaseous. 

Where the soil contains an excess of clay it is too compact, and does 
not allow the roots of plants to penetrate it without difficulty. It is also 
so dense as to prevent a free circulation of air, which is essential to the 
healthy growth of plants. After showers of short duration it becomes 
baked; a crust forms on its surface, which prevents water from pene¬ 
trating into the soil. After long rains it becomes muddy, and then 
allows the water to evaporate but slowly, and remains for a long time 
wet and cold. A sandy soil suffers from the opposite disadvantages. It 
is too porous, and does not hold firmly the roots of plants. It does not 


is it glazed ? Explain the diagram. Of what is the finest kind of earthenware 
made ? How is it glazed ? How are the ornamental designs put on ? What 
kind of glaze is sometimes put on coarse earthenware? What is said of this 
glaze ? Of what are crucibles made ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


181 


retain many of the most valuable fertilizing elements of manures, it is 
easily raised up and blown away by the wind, and it permits the rains 
at first to penetrate too deeply, and afterwards to dry up too rapidly. 
A clayey soil may therefore be improved by the addition of sand, and a 
sandy soil by the addition of clay, loam or marl. A clayey soil is im¬ 
proved by moderate burning, which renders it more porous, and promotes 
the decomposition of feldspar and other minerals which are mixed in 
with the clay. But if heated too strongly, it is converted into hard strong 
masses, which are hardly affected even by acids. Both sandy and clayey 
soils are improved by fallowing, which allows more time for their mineral 
constituents to decompose ; by draining, which carries off the excess of 
water, especially in wet weather, so that the roots of plants penetrate 
deeper into the soil, and therefore have a wider range for nourishment, 
and a greater security from the effects of drought, than plants whose 
roots extend but little ways below the surface. 

244. The common red pottery ware, and also bricks and 
tiles, are made of common clay, mixed with a portion of sand. 
The common white ware, stone-ware, tobacco-pipes, &c., are 
made of fine white clay. Stoneware is made of clay contain¬ 
ing oxide of iron and a little lime, to which it owes its partial 
fusibility. The glazing is performed by throwing common salt 
into the heated furnace. The salt is volatilized and decom¬ 
posed by the joint agency of the ware and of the vapor of the 
water always present— 

NaCl = chloride of sodium. 

HO = water. 

By double exchange. 

NaO =soda. 

[fuses into the clay.] 

HC1 = hydrochloric acid. 

[passes off as gas.] 

The soda forms a silicate which fuses over the surface of the 
ware, and gives a thin but excellent glaze. 

Earthenware. The finest kind of this ware is made of a 
white secondary clay, mixed with a considerable quantity of 
silica. The articles are thoroughly dried and fired, after which 
they are dipped into a readily fusible glaze-mixture, of which 
oxide of lead is usually an important ingredient, and when dry, 
reheated to the point of fusion of the mixture. The orna¬ 
mental designs in blue and other colors are printed on paper in 
enamel pigments mixed with oil, and transferred, while still 
wet, to the unglazed ware. When the ink becomes dry, the 
paper is washed off and the glazing completed. The coarser 
kinds of earthenware are sometimes covered with a whitish 
opaque glaze, which contains oxides of lead and tin > such 
glaze is very liable to be attacked by acids, and is dangerous 
for culinary vessels. 

Crucible s are made of clay, free from lime, mixed with 


182 


ELEMENTS OF CHEMISTRY. 


sand, or with ground ware of the same kind. Sometimes a 
mixture of plumbago and clay is used for the same purpose, 
and powdered coke with earth has been used. Crucibles 
made in this way, bear rapid changes-of temperature without 
injury. 

245. Alumina is of great value in the art of dyeing. Al¬ 
though it imparts no coloring matter itself, yet it has the 
power of fixing and deepening the colors of other substances. 
It is therefore called a mordant, (Latin, mordeo , to bite,) be¬ 
cause it causes the colors to fasten firmly to the fibre of the 
cloth. 

246. Sulphate of alumina, A1 2 0 3 +3S0 3 + 18HO. This 
salt is prepared by saturating dilute sulphuric acid with hy¬ 
drate of alumina (A1 2 0 3 ), and evaporating. It crystallizes, in 
thin pearly plates, soluble in 2 parts of water. It has a sweet, 
astringent taste, and an acid reaction. Heated to redness it 
decomposes, leaving pure alumina. 

Sulphate of alumina combines with the sulphates of potash, 
soda, and ammonia, forming double salts of great interest. 
These salts are called alums. Common alum contains 

A1 2 0 3 ,3S0 3 +K0, S0 3 +24HO. 

sulpnate of alumina, sulphate of potash, 24 eq. of water. 

Alum is therefore a double sulphate of alumina and potash, 
with 24 eq. of water of crystallization ; feldspar (p. 180) is a 
double silicate of alumina and potash. Alum reddens litmus 
paper, and dissolves in 18 parts of water at 60°, and in its 
own weight of boiling water. All the alums are soluble salts, 
with a sweet astringent taste, and all contain 24 eq. of water 
of crystallization. 

Alum is largely employed in the arts, in preparing skins, 
dyeing, &c. When it is added to a solution of coloring mat¬ 
ter, and the alumina is precipitated by an alkali, all the color¬ 
ing matter is thrown down with the precipitate, and forms 
what is called lake. The common lake used in water-color¬ 
ing is derived from madder treated in this way. Carmine is 
a lake from cochineal. In the process of dyeing, an insoluble 
compound of hydrate of alumina with the coloring matter is 
thus formed in the fibre of the cloth. 


245. What is said of the use of alumina in dyeing? 

246. Write and explain the symbol of sulphate of alumina. Mention some 
of its properties. Write and explain the symbol of common alum. What 
therefore is alum? In 475 parts of alum how much alumina?—how much 
potash ?—how much sulphuric acid ?—how much water ? 




THE ELEMENTS AND THEIR COMBINATIONS. 183 

Chromium, 6. 28. Cr. 

247. The most important ore of chromium is chrome iron 
(oxide of chrome and iron). On account of its great affinity 
for oxygen, the metal is very difficult to procure. It is whitish- 
gray, or between tin-white and steel-gray. 

248. Chromic acid , Cr0 3 , is formed by adding sulphuric 
acid to a cold and concentrated solution of bichromate of pot¬ 
ash (250) : 

KO, 2Cr0 3 ^bichromate of potash. 

S0 3 = sulphuric acid. 

Bring down KO 

KO, S0 3 ^sulphate of potash. 

[dissolved in acid solution.] 

2Cr0 3 = Chromic acid. 

[precipitates ftom acid solution.] 

The chromic acid is deposited from the mixture when cold 
in ruby-red prisms. The sulphate of potash above the crystals 
may be turned off, and the chromic acid dried on a porous 
brick. It must be kept from organic matters, which at once 
decompose it. For this purpose it should be secured under 
glass. A little of this acid thrown into alcohol, or ether, pro¬ 
duces violent action, and sets fire to the mixture. It is very 
deliquescent and soluble in water. 

249. Chromate of potash, KO, Cr0 3 , is formed on a large 
scale by heating the native chromic iron with nitrate of pot¬ 
ash. After the mass has been ignited for a considerable time, 
the product is treated with water, which dissolves out the 
chromate of potash, forming a yellow solution. This, by evap¬ 
oration, deposits anhydrous crystals of the same color. Chro¬ 
mate of potash has an alkaline reaction, and a cool, bitter, 
and disagreeable taste. It is soluble to a great extent in 
boiling water, and in two parts of water at 60°. It is insolu¬ 
ble in alcohol. 

250. Bichromate of potash, KO, 2Cr0 3 , is formed by add¬ 
ing nitric acid to a solution of the yellow chromate. One 
half of the potash is in this way removed to form sulphate of 
potash, and the bichromate crystallizes by slow evaporation in 
brilliant red, four-sided, and rectangular tables and prisms. 


247. Write the specific gravity, combining number, and symbol of chromium. 
What is the most important ore of chromium ? Mention some of the properties 
of the metal. 

248. Write the symbol of chromic acid. How is this acid formed ? Explain 
the diagram. State some of the properties of chromic acid. 

249. Write and explain the symbol of chromate of potash. How is this salt 
formed ? State some of its properties. 

250. Write and explain the symbol of bichromate of potash. State the pro¬ 
cess of preparing this salt. Mention some of its properties and uses. 



184 


ELEMENTS OF CHEMISTRY. 


Its powder is reddish-yellow. It is soluble in ten parts of 
water, and the solution has a cool, bitter, and metallic taste, 
and an acid reaction. Both the chromate and the bichromate 
of potash, are prepared on a large scale for the use of the 
calico-printer, and for making chrome yellow. 

251. Chromate of lead, chrome yellow, PbO, Cr0 3 . This 
yellow pigment is prepared by precipitation from the nitrate or 
acetate of lead, by a solution of chromate or bichromate of 
potash: 

PbO, NO 5 := nitrate of lead. 

KO, Cr0 3 =chromate of lead. 

By double exchange 

PbO, CrO 3 — Chromate of lead, insoluble salt. 

[precipitated from solution.] 

KO, NO s = nitrate of potash, soluble salt. 

[remains in solution. ] 

When boiled with lime-water, the chromate of lead loses 
half its acid, and a sub-chromate of an orange-red color is 
left. Still more of the chromic acid is removed by adding 
chromate of lead to fused nitre, and afterwards dissolving out 
the soluble salt by water. The product thus obtained is crys¬ 
talline, and rivals vermilion in beauty of tint. The abstrac¬ 
tion of chromic acid, therefore, changes chromate of lead to 
orange and red, while the addition of this acid changes the 
yellow ctiromate of potash to the red bichromate of potash. 
(See also chromate of silver, under the head of silver.) Chro¬ 
mate of lead occurs native of a beautiful orange-red color, crys¬ 
tallized in oblique rhomboidal prisms. In powder, its color is 
yellow. 

252. A salt of chromic acid is detected by the yellow pre¬ 
cipitate of chromate of lead and chromate of baryta, which it 
forms with solutions of baryta and lead. Nitrate of mercury 
forms a rich cinnabar precipitate with solutions of chromium, 
nitrate of silver a carmine changing to purple, nitrate of cop¬ 
per a chestnut-colored precipitate. The salts of chromic acid 
may be generally distinguished by their color. The neutral 
compounds of chromic acid with the alkalies are yellow ; the 
acid chromates are orange-red. These salts have exceedingly 
great coloring .power, one part of the chromate of potash colors 
perceptibly 40,000 parts of water. 


251. Write the symbol of chromate of lead. State the process of preparing 
this salt. _ Explain the diagram. What is the effect of abstracting a portion 
of chromic acid from the chromate of lead ? How is a similar effect produced 
upon the chromate of potash ? 

252. How is chromic acid detected ? How are the metals of this group dis¬ 
tinguished from those of the preceding groups ? Mention the peculiar prop¬ 
erties of the metals of this group. 



THE ELEMENTS AND THEIR COMBINATIONS. 


185 


GROUP FOURTH. 

Manganese, ' 8. 28. Mn. 


253. Manganese is somewhat abundant in nature in an 
oxidized state, forming or entering into the composition of sev¬ 
eral interesting minerals. Traces of this substance are fre¬ 
quently found in the ashes of plants. It has also been detected 
in the blood. It is a grayish-white metal, with but little me¬ 
tallic lustre, resembling some varieties of cast iron. It is des¬ 
titute of magnetic properties. When free from iron it oxidizes 
so readily that it requires to be kept under naptha. Water is 
not sensibly decomposed by manganese in the cold. Dilute 
sulphuric acid dissolves it with great energy, evolving hydro¬ 
gen. It is also oxidized rapidly by other dilute acids. 

Manganese forms an immense number of salts. Even the 
combinations with oxygen alone are very numerous 

Protoxide, MnO. 

Deutoxide, Mn 3 0 4 =Mn g 0 12 .* 

Tritoxide, „ Mn 2 0 3 =:Ma 8 Oj 2 . 

Peroxide, Mn0 2 =Mn 6 0 12 ! 

Manganic acid, Mn0 3 =Mn 4 0 12 =Mn 7 0 2 4 . 

Permanganic acid, Mn 2 0 7 = . . . Mn 6 0 21 . 


254. Peroxide of manganese, black oxide , Mn0 2 , is the 
most common ore of manganese, and the most important 
compound. It is found both massive and crystallized. It has 
a black color, is insoluble in water, and refuses to unite with 
acids. It is decomposed by hot sulphuric acid, with the evolu¬ 
tion of oxygen gas, and by hydrochloric acid, with the evolu- 
lution of chlorine (129). This oxide of manganese has con¬ 
siderable importance in commerce, on account of its uses in 
making chlorine for bleaching, and also as a component of 
glass (p. 159). 

255. Manganic acid , Mn0 3 , is not found in a free state, 
nor formed separately. It is produced when an alkali is fused 

* This form is adopted to compare the proportion of oxygen and metal which 
these compounds of manganese contain. The proper formulae are those on the 
left hand. 


253. Write the specific gravity, combining number, and symbol of manga¬ 
nese. In what state is manganese found 1 Mention some of its properties. 
What is said of the combinations of manganese ? 

254. Write the symbol of peroxide of manganese. How much manganese 
does this oxide contain ? What is said of this ore of manganese . 




186 


ELEMENTS OF CHEMISTRY. 


with an oxide of manganese. The alkali causes the manga¬ 
nese to take an additional quantity of oxygen from the air, and 
by this the oxide is converted into an acid, which unites with 
and saturates the alkali with which it is fused. When pot¬ 
ash is the alkali employed, a manganate of potash is thus 
formed in green crystals. These dissolved in water give an 
emerald-green color to the solution which almost immediately 
changes from the absorption of oxygen from the air , becoming, 
in quick succession, green, blue, purple, and finally criinson- 
red. For this reason it has been called the cameleon mineral. 
The last color is due to the presence of permanganic acid, 
which, like the manganic acid, cannot be separated from its 
combinations, but forms a salt with potash in beautiful purple 
crystals. 

256. The salts of manganese are easily detected by the 
blowpipe. With borax, they give an amethystine bead, in the 
outer flame, and a colorless one in the inner. With carbonate 
of soda, they give a green bead. This is a more delicate re¬ 
action than that with borax. 

Iron, 8. 28. Fe. 

257. To this most valuable of all the metals, the present 
civilization of the world, and the progress of the arts and sci¬ 
ences, are owing. It is probable, that its uses were but little 
known in the earlier periods of society, although we find it 
mentioned by Moses and the earlier writers of the Bible. 
Even the Romans, quite late in the history of their empire, 
employed an alloy of copper and tin in their armor, instead 
of iron. The amount of iron consumed at the present day, 
by any nation, indicates very truly its advancement in the arts 
and sciences. 

Iron must, generally, be obtained from its ore, which is 
found lying in the earth, or imbedded in rock; gold is found 
on the surface in the metallic state. The latter may, there¬ 
fore, be well known in a savage or half-civilized state of 
society, while the valuable properties of the former are entirely 
unknown. 

In the condition of oxide, iron is almost universally diffused. 
It constitutes a great part of the common matter of rocks and 


255. Write the symbol of manganic acid. How is this acid formed ? State 
some of its properties. 

256. How are the salts of manganese detected ? 

257. Write the specific gravity, combining number, and symbol of iron. 
What is said of the history of iron l How must iron generally he obtained T 
How does this metal occur ? 



THE ELEMENTS AND THEIR COMBINATIONS. 187 

soils. It is contained in plants, and forms an essential com¬ 
ponent of the blood of the animal body. As metallic iron, it 
forms at Canaan, in Connecticut, a vein about two inches 
thick, in mica-slate rock. It frequently, also, enters into the 
composition of meteorites, or stones, which fall from the air. 

258. In reducing iron from its ore, a mixture of several 
kinds is generally used, because it has been found that the iron 
is reduced more easily in this way than when only one kind is 
employed. The mixed ore is piled up along with billets, of 
wood, coal, and other combustibles, in heaps four or five feet 
high, and many feet in length and breadth. The combustibles 
are set on fire, and allowed to burn for some days until con¬ 
sumed. This roasting drives 
off the sulphur and carbonic 
acid of the ore, and renders it 
brittle. It is then broken down, 
and mixed with certain propor¬ 
tions of charcoal, coke, bitumin¬ 
ous or anthracite coal, or lime¬ 
stone, and put into a blast fur¬ 
nace. This furnace (Fig. 81.) 
is about forty or fifty feet high. 

A A are the sides of the fur¬ 
nace. They are made in such 
a way, as to be capable of bear¬ 
ing the most intense heat with¬ 
out injury. B is a hole made 
at a considerable elevation from 
the fire, for the introduction of 
the mixed materials. D D are pipes connected with bellows 
or other machines for blowing. Formerly the air was used at 
the ordinary temperature but within a few years a very great 
improvement has been effected by heating the air before it en¬ 
ters the furnace (hot blast.) Beneath the furnace there is a 
receptacle for the melted metal. 

Iron ore contains many ingredients which must be melted in 
order that the iron may flow forth. Among these one of the 
most important is silica, which is often added when it does not 
exist in sufficient quantity. Lime is also added, which forms 
with the silica a glass that melts more readily than either 
of its constituents (pp. 113, 170) separately, and flows off as 


Fig. 81. 



258. State the process for reducing iron from its ore. Explain Fig. 81. How 
are the foreign ingredients separated from the ore ? What is said of the metal 
obtained by this process ? How is it deprived of its carbon ? What are these 
furnaces usually called when employed for this purpose ? 











188 


ELEMENTS OF CHEMISTRY. 


slag, bearing with it, to a great extent, the impurities of the 
iron. 

The rnetal obtained by this process is not pure iron, but a 
combination of carbon and iron. A hundred weight when 
melted from the ore, takes up about four or five pounds of car¬ 
bon, and likewise some silicon from the silicic acid, aluminum 
from the clay, and sometimes, also, a trace of sulphur, phos¬ 
phorus, arsenic, &c. This iron is deprived of its carbon by re¬ 
melting in a reverberatory furnace (p. 159), where the fuel 
does not come in contact with the iron itself. In this furnace, 
a cheaper fuel than coal may be used, as peat. The iron is 
constantly stirred in the reverberatory furnaces, which, when 
employed for purifying iron, is generally called a puddling 
furnace. 

259. Pure iron has a white color and perfect lustre ; com¬ 
monly, however, its color is a peculiar gray. The crystalline 
form is probably a cube. In good bar iron, or wire, a fibrous 
texture may always be observed when the metal has been at¬ 
tacked by rusting, or by the application of an acid, and upon 
the perfection of this fibre much of its strength and value de¬ 
pends. Iron is the most tenacious of all the metals ; a wire 
of ^- a of an inch in diameter bears a weight of 60 pounds. It 
is very difficult of fusion, and, before becoming liquid, passes 
through a soft pasty condition. In this state it may be welded 
(p. 147), which is usually performed by sprinkling sand over 
the heated metal. This combines with the superficial film of 
oxide, forming a fusible silicate, which is subsequently forced 
out from between the pieces of iron by the pressure applied. 
Clean surfaces of metal are thus presented to each other, and 
union takes place without difficulty. The addition of man¬ 
ganese to cast iron closes its grain, and is an improvement to 
that and to steel. 

In dry air iron does not oxidize at common temperatures. 
Heated to redness, it becomes covered with a scaly coating of 
black oxide, and, at a high white heat, burns brilliantly, pro¬ 
ducing the same substance. In oxygen gas the combustion 
occurs with still greater ease. The finely-divided spongy 
material, which is formed when the red oxide is reduced by 
hydrogen (which takes the oxygen to form water), at a heat 
below redness, takes fire spontaneously in the air. Pure water, 
free from air and carbonic acid, does not tarnish a surface of 
polished iron, but the combined agency of free oxygen and 


259. Mention some of the properties of iron. Why is sand sprinkled over red 
hot iron in the process of welding 1 What is said of the relations of ii*on to 
oxygen 1 —magnetism ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


189 


moisture speedily leads to the production of rust, which is a 
hydrate of the sesquioxide. The rusting of iron is wonderfully 
promoted by the presence of a little acid vapor. Dilute sul¬ 
phuric and hydrochloric acids dissolve iron freely with the 
evolution of hydrogen. Below a red heat iron is strongly 
magnetic, but at this temperature it loses all traces of magne¬ 
tism. 

260. Protoxide of iron, FeO, has not yet been obtained in 
a separate state, as it attracts oxygen and rapidly passes into 
the peroxide. It exists combined with the acids in an exten¬ 
sive series of salts, from which it is precipitated by alkalies, as 
a hydrate of a white color, which soon darkens as it passes 
into the peroxide by the absorption of oxygen from the air. 

261. Sesquioxide of iron, Fe 2 0 3 . If some iron-filings are 
introduced into a tumbler filled with spring water, the iron 
will gradually lose its lustre, assume a black color, and be¬ 
come converted into magnetic oxide of iron. If the water is 
first boiled to expel the air and carbonic acid which it con¬ 
tains, the iron will retain its metallic lustre while it remains 
beneath the surface ; but if the water be poured off, the iron 
on coming into contact with the air will soon rust. This is 
the sesquioxide of iron with 3 eq. of water which it absorbs 
from the atmosphere, and which is the cause of the yellow color 
of rust. 

This oxide of iron is found native in the beautiful specular 
iron of Elba, and also in the red and brown hematites. It is 
slightly acted .on by the magnet. It is often of a brilliant 
red, and as ochre of various tints, is much used as a pigment. 
Ammonia precipitates it from its solutions as a bulky red pre¬ 
cipitate. 

262. Magnetic oxide, black oxide, loadstone, Fe 3 0 4 , is one 
of the most valuable of the iron ores. It is supposed to be a 
compound of the protoxide, FeO, and the sesquioxide, Fe 2 0 3 . 
The scales of iron in blacksmiths’ forges consist mainly of it. 
It is -often found in regular octahedral crystals, and is the chief 
product of the oxidation of iron at high temperatures, in the 
air and in aqueous vapor. When properly prepared, it is of a 
deep velvet-black color, without any shade of red (sesquioxide), 
and attracted by the magnet. It does not form salts. 


260. Write the symbol of the protoxide of iron. How much iron do 36 parts 
of this oxide contain ? What is said of this oxide of iron ? 

261. Write the symbol of the sesquioxide of iron. Why is this called a ses¬ 
quioxide % (p. 116.) By what experiment may the action of air and water on 
iron be illustrated ? In what forms is the sesquioxide of iron found native ? 

262. Write the symbol of the black oxide of iron. How does this ore of iron 
occur ? State some of its properties. 



190 


ELEMENTS OF CHEMISTRY. 


263. Protosulphuret of iron, FeS, is a blackish, brittle sub¬ 
stance, attracted by the magnet. It is constantly used in the 
laboratory, in the preparation of sulphuretted hydrogen (157). 
For this purpose, it is made by throwing into a red hot cruci¬ 
ble a mixture of 2 % parts of sulphur, and 4 parts of iron-filings 
or borings of cast iron. The mixture is generally added in 
small quantities at a time. It is best to exclude the air as 
much as possible. The same substance is formed when a bar 
of white hot iron is brought in contact with a roll of sulphur. 

264. Bisulphuret of iron, FeS 2 , is found in the rocks of 
every geological age. It is evidently formed in many cases by 
the gradual deoxidation of sulphate of iron (265), by organic 
matter. It exists under two allotropic forms, that of yellow 
iron pyrites, and that of white iron pyrites. The yellow iron 
pyrites has quite the appearance of brass. It occurs in cubic 
crystals, is very hard, and not attracted by the magnet. When 
exposed to heat, a sulphuret, intermediate between the bisul- 
phuret and protosulphuret, is produced. When heated, the 
bisulphuret of iron gives off fumes of sulphurous acid, and is, 
therefore, now much used in the manufacture of sulphuric 
acid (145).. 

265. Protosulphate of iron, green vitriol, FeO, S0 3 +7 
HO, may be obtained directly, by dissolving iron in dilute sul¬ 
phuric acid. It is generally prepared, on a very large scale, 
by contact of air and moisture with common iron pyrites (bi¬ 
sulphuret of iron.) This substance absorbs oxygen from the 
air and moisture, and becomes the. persulphate. Heaps of the 
material are exposed to the air until the decomposition is 
sufficiently advanced, and the salt thus produced is dissolved 
out by water, and crystallized. It forms beautiful large green 
crystals, which slowly effloresce and peroxidize in the air. 
They are soluble in about twice their weight of cold water. 
Crystals containing 4, and also those containing 2 eq. of water, 
have been obtained. Green vitrol is much used as the basis 
of all black dyes and inks, and in the manufacture of Prussian 
blue. In the arts it is called copperas. 

266. Of all the combinations of iron, steel is the most im- 


263. Write the symbol of the protosulphate of iron. How is it prepared in 
the laboratory ? State some of its properties. 

264. Write the symbol of the bisulphuret of iron. How much sulphur does 
it contain in 60 parts ? How does the symbol of this sulphuret differ from that 
of the last 1 What is said of the bisulphuret of iron ? 

265. Write and explain the symbol of the protosulphate of iron. How does 
this symbol differ from that of the sulphurets 1 How is this salt of iron obtain¬ 
ed 1 Mention some of its properties and uses. What is it called in the arts ? 

266. By what process is steel formed ? In what way is carbon brought from 



THE ELEMENTS AND THEIR COMBINATIONS. 191 

portant. It is formed by heating pure iron in contact with 
charcoal, and is a compound of iron, with a small proportion 
of carbon. In common steel the carbon rarely exceeds 2 per 
cent. It is made by a process called cementation. A suitable 
furnace is filled with alternate strata of bars of the purest 
malleable iron and powdered charcoal. Atmospheric air is 
carefully excluded from the boxes containing the bars, and the 
whole is kept for several days at a red heat By this process 
carbon penetrates and combines with the iron. This is prob¬ 
ably effected by the agency of carbonic oxide. The oxygen of 
the air in the crucible combines with the carbon to form car¬ 
bonic oxide, which coming in contact with the heated iron, is 
decomposed, and loses one half of its carbon. It then becomes 
C0 2 , or carbonic acid. It afterwards takes up more carbon, 
and thus returns to CO, or carbonic oxide, and thus the process 
is continued, the carbonic oxide acting as a carrier from the 
carbon to the heated iron. The product of this operation is 
called blistered steel, from the blistered and rough appearance 
of the bars. The texture is afterwards improved and equalized 
by welding a number of these bars together, and drawing the 
whole out under a light tilt-hammer. 

Steel holds a middle place between cast and wrought iron, 
both as to the quantity of carbon it contains, and its other 
properties. Like cast iron, when heated to redness, and 
plunged into cold water, it becomes hard and brittle; if 
cooled somewhat more slowly, it is elastic ; if cooled very 
slowly, it possessess the properties of bar iron, in being soft, 
ductile, and malleable. If heated to redness, and suddenly 
plunged into cold water, it becomes so hard as to scratch 
glass. 

For tempering coarse edge tools, as stone-chisels, (fee., the steel is 
heated up nearly or quite to redness, after which it is taken out of the 
lire and rubbed on sand to give it a bright surface, which will show the 
most delicate changes of color. This surface is watched uutil the proper 
tint is obtained, when the steel is suddenly plunged into water, and 
cooled. Instruments which require more accurate tempering are first 
hardened, and then let down by exposure to a proper degree of heat. A 
clear yellow color appeal's at about 430°, and this is the proper color for 
razors. A golden yellow is produced by a temperature of about 473°, 
and this is used for pen-knifes, (fee. At 490° a brown tint is formed 
which is the color for scissors, (fee. At 510° a purple, and at 545° to 
560° a blue appears ; the last color is that generally employed for watch- 
springs, for swords, (fee; the first that sought in the process of tempering 


the charcoal to the steel ? Why is steel formed in this way called blistered 
steel ? How is the texture of this steel afterwards improved 1 What are the 
properties of steel compared with those of cast and wrought iron ? How is 
steel tempered? What test is now often employed for the temper of steel? In 



192 


ELEMENTS OF CHEMISTRY. 


stone-chisels mentioned above. At 578° an indigo color is produced. A 
reddish-brown tint is that at which coach-springs are tempered. 

Metal baths (of metallic alloys which fuse at a comparatively low tem¬ 
perature) have been introduced into the process of tempering, which 
enable the workman to attain greater certainty in the result. The arti¬ 
cles to be tempered are plunged into these baths, which are kept melted 
at the proper temperature. 

Tempering modifies the chemical character of steel, as well as its 
physical properties. Untempered steel dissolved in acid leaves a per¬ 
ceptible residue of carbon or carburet of iron, while tempered steel 
leaves no residue when treated with acids, for the carbon is evolved as 
carburetted hydrogen. The density also of steel is changed by temper¬ 
ing. Before tempering, its density is about 7.738, and afterwards it 
sinks to 7.704. 

When manganese or silver is added in small proportions to steel, its 
properties are improved. When silver is added, the proportion should 
not exceed 1 of silver to 600 of steel. In these proportions a chemical 
compound appears to be formed, but if a greater quantity of silver is 
added, it is distinctly seen in fibres mixed in with the steel, and the alloy 
is subject to galvanic action. When the proportion of silver does not 
much exceed gfo part, the steel is rendered much harder, forges remark¬ 
ably well, and is very greatly superior to the best east-steel for cutting 
instruments. 

In fusibility, steel is midway between cast iron and bar iron, 
being less fusible than cast, but rcipre fusible than wrought 
iron. Articles of wrought iron may be superficially coated 
with steel by plunging them into melted cast iron. The 
same object may be accomplished more easily, by strewing 
ferrocyanide of potassium over the hot iron, or by rubbing 
them with a crystal of this salt. This is decomposed, and the 
carbon of the cyanogen is absorbed by the surface of the heat¬ 
ed iron, as will be explained more fully hereafter. 

Iron exists in the soil in the more soluble form, as the sul¬ 
phate, or other salt of the protoxide of iron, and in the more 
insoluble form, as sesquioxide, sulphuret, and carbonate. In 
its soluble form it is frequently taken up in such excess, as to 
be injurious to plants. The more insoluble forms are fre¬ 
quently converted into the soluble forms by either the absorp¬ 
tion or the loss of oxygen. The sulphuret by absorbing oxygen 
becomes converted into the sulphate, which being very soluble, 
will, if present in too great quantity, prove very injurious to 
plants. The sesquioxide in a soil containing much vegetable 
matter is frequently deprived of a portion of its oxygen, and 
thus rendered more soluble. But if not in excess, and in a 
form too readily soluble, the oxide of iron in the soil is bene- 


what other respect is steel midway between cast and wrought iron ? How are 
articles coated superficially with steel ? What is said of the compounds of iron 
in the soil ? —of the use of iron in medicine ? 



THE ELEMENTS AND THEIR. COMBINATIONS. 


193 


ficial by absorbing ammonia, and probably other gaseous sub¬ 
stances and vapors from the atmosphere. A red iron soil is 
improved by frequent ploughing, and by fallowing, because, in 
this way, it is brought more perfectly into contact with the 
oxygen of the air, and the sesquioxide is therefore less liable 
to loose oxygen, and to become converted into a more soluble 
form. 

Many of the compounds of iron are employed in medicine. 
These preparations are powerfully tonic, raising the pulse, 
promoting the secretions, and increasing the coloring matter 
of the tdood. 


Zinc. 7. 33. Zn. 

267. Zinc is not found native, but a peculiar red oxide of 
zinc abounds at Stirling, New Jersey, and the native carbon¬ 
ate, or calamine , is found abundantly in many places. 

Ores of zinc, like those of iron (258), are first roasted, to 
drive off the sulphur or carbonic 
acid with which they are com¬ 
bined. They are then mixed 
with i their weight of char¬ 
coal, and placed in a large cru¬ 
cible in a furnace (Fig. 82.) 

A second crucible is cemented 
on the first and an iron tube, 
open at both ends, passes through 
the bottom of the lower cruci¬ 
ble. This tube extends down¬ 
wards through the bars of the 
furnace, into a tube below. 

When the heat is applied, the 
charcoal in the crucible decomposes the ore uniting with its 
oxygen, to form carbonic oxide, which passes off through the 
iron tube. The metal, thus reduced, also volatilizes, passes off 
with the carbonic oxide, and condenses in the tube below 
while the carbonic oxide escapes into the air. 

268. Zinc is a bluish-white metal, tough at common tem¬ 
peratures, but very brittle at the point of fusion, which is 773°. 
At a heat a little above that of boiling water, or from 210° to 
300°; it is laminable and ductile; henee, it is drawn out into 


Fig. 82. 



267. Write the specific gravity, combining number, and symbol of zinc. How 
does zinc occur 1 Describe the process for procuring zinc. Explain h lg. 82. 

268. State some of the properties of zinc. In what two ways is galvanized 
iron protected by the zinc ? Ans.—First, the zinc, after being covered with a 




























194 


ELEMENTS OF CHEMISTRY. 


wire, and rolled into sheets, and after being treated in this 
manner, or hammered at this temperature, it retains its mal¬ 
leability when cold. When slowly cooled it crystallizes. By 
exposure to the air it is oxidized on the surface, but afterwards 
suffers little change. For this reason iron is coated with zinc 
(galvanized iron, 77,) to protect it from the weather. When 
fused in an open crucible zinc absorbs oxygen from the air, 
and forms the white oxide called the flowers of zinc. If the 
crucible is covered, and heated to full redness, on removing the 
cover the zinc bursts into a flame, and burns with a brilliant 
white or greenish light. The combustion is so violent, that 
the oxide, as it is formed, is carried up into the air. Dilute 
acids dissolve zinc very readily. By its powerful 
Fig. 83. attraction for oxygen, zinc decomposes a great num¬ 
ber of salts and metallic solutions, and precipitates 
the metal from them. In this manner it precipitates 
lead from the acetate of lead in the arborescent form 
(Fig. 83). This is usually called the zinc-tree, al¬ 
though in fact it is composed of lead. Zinc is harder, 
yet lighter than lead, cheaper than copper, and less 
liable than iron to be destroyed by air and water. 
Its uses, therefore, are very numerous and impor¬ 
tant. It is employed for making nails, gasometers, gas-pipes, 
gutters for covering roofs of houses, for lining refrigerators, 
&c. 

On account of its great combustibility, zinc is sometimes used 
in fireworks. When mixed with nitre and dropped into a 
red-hot crucible it detonates violently. At a heat of about 
770°, zinc melts, and forms a grey film of suboxide, which after 
a time assumes a yellow color, and is converted into oxide of 
zinc (ZnO). As this oxide cools, it passes to a white color, 
and by this change of color of its oxide, zinc may be distin¬ 
guished from other metals. 

269. All the salts of zinc are poisonous, and excite when 
introduced into the stomach violent vomiting. Milk, white of 
eggs, and coffee, are employed as antidotes. Zinc plate is not 
proper for culinary vessels, as it is easily acted on by vegetable 
acids. 


film of oxide, does not rust as easily as iron. Secondly, by galvanic principles, 
the iron cannot rust as long as a particle of zinc remains. What experiment 
illustrates the combustibility of zinc? Explain Fig. 83. What change of 
oolor is produced in the oxide of zinc by heat ? 

269. What is the action of the salts of zinc on the system ? What antidotes 
are employed ? 









THE ELEMENTS AND THEIR COMBINATIONS. 


195 


Nickel, 9. 30. Ni. 

270. This metal is found in considerable abundance, in 
some of the metal-bearing veins of the Hartz mountains, and 
in a few other localities, chiefly as arseniuret. In this country 
it has been obtained at Chatham, Ct., and also at Mine la 
Motte in Missouri. It has been found as a beautiful green hy¬ 
drous carbonate in Lancaster Co., Pa. 

Nickel is almost always found alloyed in masses of meteroric 
iron. It is a white malleable and ductile metal, and takes a 
high polish. It does not fuse below 3,000°. It is not as easily 
oxidized as iron, since it is but little attacked by dilute acids. 
It is one of two or three magnetic metals, and magnets may 
be made of it, nearly as powerful as those of iron. At 660° it 
loses its magnetic power. Its chief use is in making G-erman 
silver, a compound of copper 100 parts, zinc 60, nickel 40. If 
the ores of nickel were more abundant and rich, this metal 
would be employed in the arts, as it possesses all the properties 
'‘which can render a metal useful. 

Cobalt, 8*5. 30. Co. 

271. Cobalt, nickel, andiron, have a great similarity, both 
in their external appearance and in their properties. The two 
first are constantly found associated in nature, and are obtained 
from their ores by similar means. Cobalt and nickel have less 
attraction for oxygen than iron, or do not acquire rust so 
easily, and are therefore called nobler metals. All these 
metals are magnetic ; if pure, however, cobalt would, proba¬ 
bly, be found not magnetic. Cobalt is a reddish-white, brittle 
metal, which melts only at a very high temperature. It is 
but feebly attacked by dilute hydrochloric and sulphuric acids, 
and remains in the air unchanged. 

272. Protoxide of cobalt, CoO, is a grayish-pink powder, 
very soluble in acids. It affords salts of a fine red or pink 
color. When the cobalt solution is mixed with caustic potash, 
a beautiful blue precipitate falls, which, when heated, becomes 
violet, and at length, a dirty red. These alterations in color,* 


270. Write the specific gravity, combining number, and symbol of nickel. 

How does this metal occur ? State some of its properties. What is the com¬ 
position of German silver ? . _ , 

271. Write the sp. gr., com. num., and sym., of cobalt. What is said ot the 
resemblance between cobalt, nickel, and iron ? Why are cobalt and nickel 
called nobler metals than iron ? Mention some of the properties of cobalt. 

272. Write the symbol of cobalt. State some of its properties. Ol what 
does smalt consist? In what way is a fine black color given to glass ? 




196 


ELEMENTS OF CHEMISTRY. 


are owing to a change in the state of hydration. Both this 
anfi the peroxide of cobalt (C0 2 0 3 ), communicate a splendid 
blue color to glass. By this reaction with a bead of borax un¬ 
der the blowpipe oxide of cobalt may be detected. The sub¬ 
stance called smalt , used as a pigment, consists of glass colored 
by the oxide of cobalt. Writing paper is prepared with a 
faint blue tinge, by adding a little of this substance in powder. 
A fine black color is given to glass by a mixture of the oxides 
of cobalt, manganese, and iron. 

273. Chloride of cobalt , CoCl, is easily prepared by dis¬ 
solving the oxide in hydrochloric acid. It gives a deep rose- 
red solution, which, when sufficiently strong, deposits hydrated 
crystals of the same color. When the liquid is evaporated to 
a very small bulk, it deposits anhydrous crystals which are 
blue ; these also form a red solution on contact with water. 
A dilute solution of chloride of cobalt forms a blue sympathetic 
ink, which is so pale, that the letters formed with it are invis¬ 
ible, until they are rendered anhydrous by heat, when they 
appear of a blue color. These soon absorb moisture, and again 
become invisible. G-reen sympathetic ink is formed by a 
mixture of the chlorides of cobalt and nickel. 

274. Cobalt is precipitated violet-blue, by potash and soda ; 
red, by carbonate of potash and carbonate of soda ; green, by 
yellow prussiate of potash ; brownish, by red prussiate ; black, 
by an alkaline sulphuret; and gray, by the chromate of potash. 


FIFTH GROUP. 

Bismuth, 10. 71. Bi. 

275. Bismuth is obtained from its ore by a very simple 
process. Its melting point is so low, that all that is necessary is 
to heat it to about two and a half times the temperature of 
boiling water, on an inclined plane, when the bismuth melts 
and flows off below, while the other metals or ores with the 


273. Write the symbol of chloride of cobalt. How is this chloride prepared ? 
State some of its properties. How does this group of metals differ from the 
preceding groups ? (195.) State the peculiar properties of this group (195.). 

275. Write the sp. gr., com. num., and sym. of bismuth. State the process 
for obtaining bismuth. How does this metal occur % Explain Eig. 84. What 
other properties of bismuth are mentioned ? 




THE ELEMENTS AND THEIR COMBINATIONS. 197 

gang , remain behind unmelted. It is found native, and also 
in combination with oxygen, ar¬ 
senic, and sulphur. Native bis- Fig.84. 

muth is found at Monroe, Conn. 

It is brittle, but may be somewhat 
extended by careful hammering. 

Its color is reddish tin-white, and 
its lustre moderate. It melts at 
482°, and crystallizes in cubes. The 
crystallization of a mass of this 
metal (Fig. 84,) is very peculiar, 
and resembles very much a work of 
art. As it solidifies from fusion, it expands at least part 

276. With other metals bismuth forms alloys, which melt 
at a very low temperature. An alloy of equal parts of bismuth, 
lead, and zinc, is so fusible that it may be melted in moderately 
hot water. An alloy of bismuth, lead, and tin, is made into 
spoons, which, when dipped into hot tea, melt in the cup ; yet 
the melting points of the constituents of this alloy are com¬ 
paratively high, that of bismuth being 476°, that of lead 612°, 
and that of tin 442°, while the alloy melts at the heat of boil¬ 
ing water, or 212°. This fusible metal has lately been ob¬ 
tained in crystals, showing that it is a true chemical compound. 
As these alloys in their melted state do not burn wood, they 
are also well adapted for making metallic copies of engraved 
wooden moulds for calico printing, and block impressions. 

Bismuth is detected by the decomposition of its nitrate by 
water. When a solution of nitrate of bismuth is poured into 
a large quantity of water, it is immediately decomposed with 
the production of a copious white precipitate of subnitrate of 
bismuth. This is owing to the superior basic power of the 
water which takes a part of the nitric acid. Some of the 
compounds of antimony are decomposed in the same way, but 
these may be distinguished from salts of bismuth by the addi¬ 
tion of tartaric acid, which either dissolves or prevents the for¬ 
mation of the basic salt of antimony. 

Copper, 9. 32. Cu. 

277. Copper is found in the United States in masses of im¬ 
mense magnitude. One mass from Lake Superior weighed 
over 3,000 pourtds. It is distinguished from all the* other 



276. What is said of the alloys of bismuth 1 To what use are these alloys 
sometimes applied ? How is bismuth detected ? 

277. Write the sp. gr.,com. num., and sym. of copper. How does this metal 



198 


ELEMENTS OF CHEMISTRY. 


metals, except titanium, by its red color. It receives a consid¬ 
erable lustre in polishing. It is both malleable and ductile, 
and at the same time very strong and tenacious, so that it may 
be hammered out into plates, which, even when very thin, 
still hold firmly together. It has a slightly nauseous taste, 
and emits a disagreeable smell when rubbed. The use of cop¬ 
per for galvanic purposes, as in telegraph wire, and in the 
construction of the helices for the battery, is owing to its great 
power of conducting electricity, to the ease with which it is 
bent and wound, and to the fact that it is less liable to rust 
than iron. In dry air, copper undergoes no change, but by a 
moist air, it becomes covered with a strongly adherent green 
crust, consisting, in a great measure, of carbonate. Sheet 
Copper is employed for sheathing ships, for roofing towers and 
other buildings, as it is not so liable to rust as iron. Copper¬ 
plate engravings are preferred on account of their durability. 
For the same reason, copper is employed for the rollers of print 
works. It quickly oxidizes, when heated to redness in the 
air, and becomes covered with a black scale (black oxide). 
It does not fuse below 2,200°. It is, therefore, excellently 
adapted for such articles as are to be exposed to a great heat, 
as for kettles, boilers, moulds for casting, &c. 

Dilute sulphuric and hydrochloric acids hardly act on cop¬ 
per ; boiling sulphuric acid attacks it with an evolution of 
sulphurous acid (141). Nitric acid, even dilute, dissolves it 
readily. It is stiffened by hammering and rolling, while zinc 
is rendered malleable by the same process. It is softened by 
heating and plunging into cold water, while iron is rendered 
brittle in the same way. 

278. Copper is hard and elastic, and therefore sonorous. 
Bell-metal is an alloy of about 3 of copper to 1 of tin. Chi¬ 
nese gong m,etal is 4 of copper to 1 of tin. Bronze differs 
from bell-metal in having less tin. In this the proportion 
varies from } to y 1 ^. By the union of copper and zinc, a metal 
of a great variety of tints and shades of color may be produced. 
Brass consists of 4 of copper to 1 of zinc. A lighter colored 
brass is formed of copper 2, zinc 1. Pinchbeck is made of 
zinc 1, and copper varying from 4 to 11 or 12. With this 
great proportion of copper, its color is almost that of gold, and 
it is, therefore, employed in the manufacture of trinkets and 

occur ? What are some of its properties ? To what is the value of copper 
for galvanic purposes owing? Why is sheet copper employed for roofing? 
Why is copper used for engravings ? What other properties of copper are 
mentioned ? 

278. What is the composition of bell-metal ?—gong-metal ?—bronze ?—brass? 
—pinchbeck ? Why are gold and silver alloyed with copper ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


199 


toys, which are intended to resemble gold. Gold and copper 
form common gold ; silver and copper, common silver, from 
which gold and silver articles and coins are made. The cop¬ 
per serves to harden the silver and gold, and to render articles 
made of these metals more durable. 

279. Protoxide of copper, black oxide , CuO, is the base of 
all the blue and green salts of copper. It is most conveniently 
prepared, by heating to redness nitrate of copper, which suf¬ 
fers complete decomposition, the nitric acid being driven off 
and the black oxide remaining. 

Black oxide of copper is used in analysis, to determine the 
amount of hydrogen which the substance under examination 
contains. For this purpose it is mixed with the substance to 
be analyzed and the whole is gradually brought to a red heat, 
at which temperature the hydrogen from the substance under 
examination takes oxygen from the black oxide, and passes 
over in a state of vapor into a chloride of calcium tube (Fig. 78), 
where it is absorbed. The increase of weight in the chloride 
of calcium tube shows the amount of water formed, and conse¬ 
quently the hydrogen, which is ■§• part of the water. 

280. Suboxide of copper , red oxide , Cu 2 0, is found native 
in beautiful octahedral crystals. It is also formed when cop¬ 
per is oxidized by heat, and is the red slag which forms during 
the calcination and fusion of copper. This oxide communicates 
to glass a splendid ruby-red color, while the protoxide of copper 
produces green. 

281. Sulphate of copper , Hue - vitriol, CuO, S0 3 +5H0. 
This salt crystallizes in large, beautiful, blue rhombs, which 
are soluble in 4 parts of cold, and 2 of boiling water. It loses 
its water by a gentle heat, and falls to a white powder. It is 
much used in dyeing. With ammonia it forms a dark blue 
crystalline compound. 

282. Nitrate of copper, CuO, N0 5 -f-3H0, is made by dis¬ 
solving copper in nitric acid to saturation. It forms deep blue 
crystals, very soluble and deliquescent. It is highly corrosive. 

Ammonia detects the smallest traces of copper in solution, 
by the deep violet-blue of the ammoniacal salt of copper 
which is formed. Iron precipitates it from its solution, as a 


279. Write the symbol of black oxide of copper. How is this oxide prepared ? 
For what purpose is it employed in chemical analysis ? How is this accom¬ 
plished ? 

280. Write the symbol of the suboxide of copper. In what form does this 
oxide occur ? How is it formed 1 To what use is it applied ? 

281. W rite the symbol of sulphate of copper. What is said of this salt. 

282. Write the symbol of nitr&tQ of copper. State some of its properties. 
What tests of copper are mentioned ? 



200 


ELEMENTS OF CHEMISTRY. 


brilliant red coating. A knife blade is a test for copper, by 
which it is plated when dipped into any of the solutions of that 
metal. 

Lead, 11. 104. Pb. 

283. Next to iron, lead is the most widely diffused and the 
cheapest metal. It has been known from the earliest ages of 
the world. In this country it is found in immense quantities, 
occurring in numerous states, particularly in that of sulphuret 
of lead or galena. The lead region extends from Wisconsin in 
the north, to the Red river of Arkansas in the south, and in 
breadth about 150 miles. Lead is reduced in the same man¬ 
ner as other ores, first by roasting the ore to drive off the sul¬ 
phur, and thus to convert the sulphuret into an oxide. This 
is then heated with a limited amount of fuel in a flame or 
blast furnace. The ignited charcoal takes the oxygen of the 
oxide of lead to form carbonic acid, which flies off and reduces 
the metal. 

A second mode of reducing lead from the sulphuret, consists 
in heating the ore with a metal which has a greater affinity 
for sulphur than lead has, and therefore replaces the lead. 
When iron is used for this purpose, the iron and sulphuret of 
lead become lead and sulphuret of iron. 

Lead is a soft, bluish-white metal, possessing very little 
elasticity. It has a perceptible taste, and a peculiar smell 
when rubbed. It is flexible, and may be easily rolled out 
into plates, and drawn into coarse wire, but this has exceed¬ 
ingly little strength. It melts at 610° or a little above, and 
at a white heat boils and volatilizes. By slow cooling, it may 
be obtained in octahedral crystals. In the air it oxidizes 
rapidly, forming a coat of oxide or carbonate, which protects it 
from further corrosion. When melted, it rapidly combines 
with oxygen from the air, forming either the protoxide or the 
red oxide, according to the heat. At a moderate heat, lead 
may be mixed with gold or silver, but when the heat is in¬ 
creased the lead rises to the surface combined with all the 
heterogeneous matters. Upon this property of lead is founded 
the art of refining the precious metals. 

Lead does not easily dissolve in dilute acids, except in nitric ; 
with this acid it forms a soluble salt, and when heated with 
strong sulphuric acid, it dissolves, forming a nearly insoluble 
sulphate of lead. 


283. Write the sp. gr., com. num., and sym. of lead. What is said of the 
abundance and the forms in which lead occurs. How is lead reduced from its 
ore ? What is the second method ? State some of the properties of lead. 



THE ELEMENTS AND THEIR COMBINATIONS. 201 

284. Protoxide of lead, litharge, massicot f PbO. This 
oxide is a yellow powder, formed by slowly oxidizing' lead 
with heat. It is slightly soluble in water, and the solution is 
alkaline. At a red heat it melts, and tends to crystallize*on 
cooling. In a melted state it attacks and dissolves siliceous 
matter with astonishing facility, often penetrating a crucible 
in a few minutes. It is therefore used in glazing pottery, and v 
in the manufacture of glass. When heated with organic sub¬ 
stances it is easily reduced, the hydrogen and carbon of which 
take its oxygen to form water and carbonic acid. 

Red oxide of lead, red lead, Pb 3 0 4 , is a common pigment 
formed by exposing melted lead to a temperature of 600° or 
700°. It is a brilliant red and extremely heavy powder, de¬ 
composed with evolution of oxygen by strong heat. Its com¬ 
position, therefore, varies with the heat at which it is prepared. 
It is preferred to litharge in glass-making, and is commonly 
used as a red coloring matter. 

285. Carbonate of lead, white lead, PbO, C0 2 , is some¬ 
times found beautifully crystallized in long white needles, ac¬ 
companying other metallic ores. It is manufactured to an 
immense extent for the use of the painter. There are three 
processes in all of which the acetate of lead is first formed, 
which is afterwards decomposed by carbonic acid. In theJirst, 
called the French process, carbonic acid is conducted into a 
solution of basicf acetate of lead. The excess of base in this 
salt of lead, is precipitated by carbonic acid as carbonate of 
lead or white lead. The acetate of lead thus rendered neutral, 
will dissolve a fresh quantity of oxide of lead, with which it is 
digested, and it is afterwards again treated with carbonic acid. 
This process is repeated until a large quantity of white lead is 
formed from a small quantity of the acetate. As thus ob¬ 
tained, the carbonate of lead has a dazzling white color, but 
does not possess the body of white lead prepared by the Eng¬ 
lish and Dutch methods. 

In the English method, oxide of lead (litharge) is mixed 
with vinegar (acetic acid) to form a paste of acetate of lead. 
This is then spread upon a stone slab, and exposed to the fumes 

* Called litharge when fused, massicot when in a pulverulent state, 
t Acetate of lead with an excess of base, or excess of lead. 


284. Write the symbol of the protoxide of lead. What is said of this oxide 
of lead ? For what purposes is it used ? Write the symbol of the red oxide 
of lead ? What is said of this oxide 1 

285. Write the symbol of carbonate of lead. How is this substance found? 
Describe the French process for making white lead. What is said of the lead 
prepared in this way ? Describe the English method;—the Dutch. 

9 * 



202 


ELEMENTS OF CHEMISTRY. 


of burning coke, the carbonic acid of which reduces the basic 
acetate to the neutral salt, as in the previous case, and pre¬ 
cipitates the excess of lead as carbonate of lead. 

T3y the Dutch method , a large number of jars containing 
vinegar are arranged in a building on a layer of stable manure 
or tan, and rolls of sheet lead are suspended in the jars above 
the vinegar. The whole is then covered with another layer 
of stable manure. After several months, the rolls of lead are 
found to be mostly, if not entirely, converted into carbonate of 
lead. The design of the tan or manure is to produce a high 
temperature by fermentation, and to furnish carbonic acid to 
the lead to form carbonate of lead. This heat causes the vine¬ 
gar to rise in vapor, and attack the lead, forming basic acetate 
of lead, which is decomposed by the carbonic acid given off in 
fermentation, and reduced again to the neutral acetate. This 
a second time attacks the lead, and thus the process is con¬ 
tinued as before. 

286. Pure water readily attacks lead, and converts it into a 
hydrated oxide ; in this case water acts the part of an acid, for 
as acids first oxidize, and then unite with bases, so water, in 
this case, first converts the lead to an oxide, and then unites 
with this oxide to form a hydrate. This hydrate is, to a con¬ 
siderable extent, soluble in water, and therefore, when 'pure 
water is conducted through lead-pipes, it is rendered poisonous. 
But spring and well water almost always contain sulphates 
dissolved. When these are present, they are decomposed ; 
their sulphuric acid unites with the oxide of lead, and forms a 
coating on the pipes of insoluble sulphate of lead, and the pipes 
are thus protected from further corrosion. The water therefore 
passes through them free from lead. Several other salts have 
precisely the same action as the sulphates. When the water 
contains only carbonic acid, a carbonate of lead is formed, 
which is slightly soluble, and which, therefore, renders the water 
poisonous. Pipes coated with tin are now made, which ob¬ 
viate all danger from this source. 

Lead is cast in sheets by letting it run out of a horizontal slit 
in a box which is drawn along the table. The Chinese cast 
it extremely thin in this way, on cloth, for lining chests of tea. 
A small portion of tin is added to the lead used for this purpose ; 
the thinnest sheets contain the most tin, and are used for en- 


286 . What is the effect of pure water upon lead ?—spring water ? What 
is the action of water containing sulphates upon lead pipes ? How is lead cast 
into sheets ? State the constituents of plumbers’ solderfine solder shot. 
What is the test for lead ? 



THE ELEMENTS AND THEIR COMBINATIONS. 203 

closing the best teas. Lead is also rolled out to the proper 
degree of thinness. The melted lead is often poured on a flat 
stone, and another flat stone brought down suddenly upon it, 
by which it is pressed out into a thin sheet. The edges are 
then trimmed, and the sheets soldered together for use. 

An alloy of lead 2, and tin 1, constitutes 'plumbers' solder ; 
these proportions reversed give a more fusible compound called 
fine solder. The lead employed in the manufacture of shot, 
is combined with a little arsenic, which has the effect to render 
the drops more perfectly globular. 

The test for lead is sulphuric acid. Into a wine-glass, half 
full of water, drop a single drop of sulphuric acid, and add a 
little nitrate of lead. This small quantity of sulphuric acid 
will form a white precipitate of the insoluble sulphate. 

Mercury, 13-5. 100. Hg.* 

287. Mercury is the only metal which is liquid at the ordi¬ 
nary temperature. It is occasionally met with in globules 
disseminated through the native sulphuret. It is sometimes 
also seen running in small streams at the bottom of the mines. 
The sulphuret, sometimes called cinnabar , is found in consid¬ 
erable quantity in several localities, chiefly in Spain and Car- 
niola. From this ore mercury is obtained by heating it in an 
iron retort with lime or with scraps of iron, which take away 
the sulphur, or by roasting it in a furnace from which its fumes 
are conducted into a large chamber, where they are condensed 
into metallic mercury and sulphurous acid. Mercury is im¬ 
ported into this country in bottles of hammered iron, contain¬ 
ing 60 or 70 pounds each, and in a state of considerable pu¬ 
rity. When purchased in smaller quantities, it is sometimes 
adulterated with tin and lead, which metals it dissolves to 
some extent, without much loss of fluidity. This admixture 
may be known by the foul surface the mercury exhibits when 
shaken in a bottle containing air, and by the globules leaving 
a train when made to roll upon a table. 

Pure mercury is a brilliant metal, of a color nearly silver- 
white. It is nearly unchanged by air, but, after a long expo¬ 
sure, it grows dull, uniting with the oxygen of the air, and 
forming a small portion of oxide. This takes place more 
readily in summer. It solidifies at—40°, and crystallizes in 

* Latin, hydrargyrum. 


287. Write the sp. gr., com. num., and sym. of mercury. What is said of 
this metal ? What is the most common ore of mercury 7 Where is this 






204 


ELEMENTS OF CHEMISTRY. 


brilliant, regular octahedrons ; in this state it is soft and mal¬ 
leable, and may be cut with a knife like gold, silver, and pla¬ 
tinum, which are all very soft when pure. At 662° it boils, 
and yields a transparent, colorless vapor, of great density. 
This vapor condenses on cold surfaces, in minute, brilliant 
globules. Even at 60°, a very rare vapor of metallic mercury 
rises from its surface. At 32° this is nearly or quite imper¬ 
ceptible. When kept in vessels to which air has free access, 
at a temperature near its boiling point, or above 600°, it 
gradually becomes converted into a deep-red, crystalline sub¬ 
stance, which is the peroxide or red oxide of mercury. At a 
dull red heat this oxide is again decomposed into its constit¬ 
uents. 

Hydrochloric acid has little or no action on mercury ; the 
same is true of dilute sulphuric acid, but concentrated sul¬ 
phuric acid, when boiling hot, oxidizes mercury, converting it 
into a sulphate of the red oxide with the evolution of sulphur¬ 
ous acid. Nitric acid, even dilute and cold, dissolves mercury 
freely. 

288. Protoxide of mercury , HgO, is prepared in the large 
way by heating the nitrate very cautiously, until it is quite 
decomposed, and a brilliant red crystalline powder left. It 
may also be formed by heating metallic mercury for a long 
time in a glass vessel nearly closed. It is slightly soluble in 
water, and its solution has an alkaline reaction and metallic 
taste. It is highly poisonous. 

289. Subchloride of mercury , calomel, Hg 2 Cl, is always 
produced when chlorine comes in contact with mercury at 
common temperatures. It is sometimes, though rarely, found 
native, forming horn quicksilver , so called from its appear¬ 
ance. From the perchloride (290), it is distinguished by its 
insolubility, and by its forming a black compound with am¬ 
monia, while the perchloride forms a white compound. At a 
temperature below redness, it rises in vapor and sublimes, 
forming a yellowish-white, crystalline mass. Like the chlo¬ 
ride of silver (297), it is insoluble in cold and dilute, but solu¬ 
ble in strong and boiling hot nitric acid. 

290. Perchloride of mercury , corrosive sublimate, HgCl. 


found 1 How is metallic mercury obtained from cinnabar ? Mention some of 
the properties of mercury 1 What is said of the action of acids on mercury 1 

288. Write the symbol of the protoxide of mercury. How is this substance 
prepared ? State its properties. 

289. Write the symbol of the subchloride of mercury. How is this substance 
produced ? How is it distinguished from the perchloride ? State some of its 
properties. 

290. Write the symbol of the perchloride of mercury. How does this sym- 



THE ELEMENTS AND THEIR COMBINATIONS. 


205 


When metallic mercury is heated in chlorine, it takes fire and 
hums, producing this substance. It may also be made by 
dissolving the red oxide in hot hydrochloric acid, when crystals 
of coirosive sublimate separate on cooling. The most common 
method is to sublime a mixture of equal parts of mercury and 
common salt. 

The sublimed chloride is a white, transparent, crystalline 
mass of great density. It melts at 509°, and boils and vola¬ 
tilizes at a somewhat higher temperature. It is soluble in 16 
parts of cold, and 3 of boiling water, and crystallizes very beau¬ 
tifully from a hot solution in long white prisms. Alcohol and 
ether dissolve it with facility ; the latter even withdraws it 
from a watery solution. Chloride of mercury combines with a 
great number of other metallic chlorides, forming a series of 
beautiful double salts. It absorbs ammoniacal gas with great 
avidity. The aqueous solution is decomposed by light, part of the 
chlorine separates from the salt, calomel is deposited, and the 
solution becomes acid. Calomel, on the other hand, is decom¬ 
posed by light into a gray powder, consisting of a mixture of 
mercury and corrosive sublimate. In crystals corrosive subli¬ 
mate is not injured by light. Many animal and vegetable sub¬ 
stances convert corrosive sublimate into calomel. Some sub¬ 
stances effect this change slowly, while others, and especially 
albumen (white of eggs, &c.), produce it in an instant. Hence 
the solution of the white of eggs is an antidote to this poison. 

Like most poisonous substances, corrosive sublimate possesses 
antiseptic properties in a high degree. For this reason wood 
employed in ship building and sleepers for railroads, are some¬ 
times saturated with a solution of it in water. This process 
is called Kyanizing. The plants of herbariums, and small 
animals, may be preserved by being passed through an alco¬ 
holic solution of corrosive sublimate. 

291. Suljphuret of meixury, Vermillion, cinnabar , HgS, is 
formed by passing sulphuretted hydrogen through a solution 
of corrosive sublimate. The black precipitate which is formed, 
is sublimed, and becomes dark red and crystalline, but under¬ 
goes no change of composition. This substance is most easily 
produced by subliming an intimate mixture of 6 mercury and 
1 sulphur, and reducing to a very fine powder the resulting 


bol differ from that of the last substance ? How is the perchloride of mercury 
formed ? Mention some of its properties. What is the antidote for corrosive 
sublimate ? How does albumen render this substance harmless ? What other 
properties of corrosive sublimate are mentioned ? 

291. Write the symbol of sulphuretqf mercury. How is it prepared ? State 
its properties ? 



206 


ELEMENTS OF CHEMISTRY. 


cinnabar ; the beauty of the tint depends very much upon the 
extent to which the division is carried. 

This is the most common ore of the quicksilver mines. 
When heated in the air it yields metallic mercury and sulphur¬ 
ous acid. It resists the action of caustic alkalies in solution, 
and is not acted on by strong mineral acids. It is attacked only 
by aqua-regia, 

292. The different salts of mercury have a great variety of colors ac¬ 
cording to the amount of oxygen which they contain, and according to 
the mode in which they are prepared. Nitric acid, for example, with¬ 
out heat dissolves mercury, forming a protoxide (a protonitrate); with 
heat it forms a peroxide (pernitrate); if ammonia be added to the first 
solution, a black precipitate is formed; but with the second a white pre¬ 
cipitate occurs. 

Protoxide of mercury is either red or yellow, according to the mode 
in which it is prepared. These are allotropic forms, for they have dif¬ 
ferent properties, but the same composition. The yellow oxide, when 
not calcined, is attacked by chlorine with much greater facility than the 
red oxide. It combines in the cold with oxalic acid, while the red ox¬ 
ide is not attacked by this acid. An alcoholic solution of the perchloride 
of mercury converts the yellow oxide into the black oxichloride, while 
it has no action upon the red oxide. A solution of iodide of mercury, pre¬ 
pared by mixing iodide of potassium with perchloride of mercury, is ob¬ 
tained as a precipitate which is at first yellow, but in a few moments 
changes to a most brilliant scarlet, and retains this color on drying. The 
yellow crystals, which are at first found with the precipitate, break up 
and disappear as the salt passes to its red modification. If suddenly ex¬ 
posed to a high temperature, the iodide of mercury becomes yellow 
throughout, and sublimes in minute, but brilliant yellow crystals. If 
touched with a hard body in this state, it instantly becomes red, and the 
same change happens spontaneously after some time. By very slow and 
careful heating, a sublimate of red crystals of a totally different form is 
obtained, which are permanent. 

293. Mercury unites with most of the other metals, the 
tenacity of which, and in most cases the value, is destroyed by 
the compound. All the salts of mercury volatilize and decom¬ 
pose at a temperature of ignition. If a piece of cinnabar is 
placed in a tube, and a bright slip of copper also inserted, on 
heating the cinnabar the mercury will sublime and attach 
itself to the copper. Those salts of mercury which fail to yield 
the metal by simple heating, may in all cases be made to do 
so by adding “a little dry carbonate of soda. A drop of any 
solution of mercury will coat a polished surface of gold with a 
white amalgam, the instant that the point of a knife is intro- 


292. What is said of the different salts of mercury ? What is the action of 
heat on the salts of mercury ? By what experiment may this be illustrated ? 
What is sometimes added to these salts to reduce the metal ? What other tests 
of mercury are mentioned ? 




THE ELEMENTS AND THEIR COMBINATIONS. 207 

duced into the solution. The soluble compounds of mercury 
also whiten a slip of copper by depositing metallic mercury on 
its surface. An ore of mercury may be easily detected by 
crushing it and throwing some of the powder on a hot plate 
of iron, or on a hot brick covered with iron filings, and invert¬ 
ing over it a glass of any kind. If any mercury is contained 
in the mineral, it will rise and attach itself in small globules 
to the sides of the glass. 

Silver, 10-5. 108. A g.* 

294. The mines of Mexico and the southern Andes, furnish 
by far the greater part of the silver of commerce. Many 
mines of this metal are, however, found in Spain, Saxony, and 
the Hartz mountains. G-alena (283.) is also a constant source 
of silver, and is rarely quite free from this precious metaL 
Silver often occurs native, and also in combination with sul¬ 
phur. 

Silver has the clearest white of all the metals, and is capa¬ 
ble of receiving a lustre surpassed only by polished steel. In 
malleability and ductility it is inferior only to gold. When 
pure it is very soft, so that it may be cut with a knife. It does 
not rust when exposed to air or moisture : sea air, however, 
corrodes it on account of the salt which it contains. It is acted 
on by solutions of common salt which forms with it a double 
chloride of sodium and silver. It is, probably, the best con¬ 
ductor of heat and electricity known. 

Pure silver melts at 1873° or at a bright red heat. When 
melted it absorbs oxygen in considerable quantity, amounting 
sometimes to 22 times its volume. In becoming solid, it parts 
with the whole of this oxygen, and this produces the granular 
appearance of silver when hastily cooled. This effect is en¬ 
tirely prevented by a small per centage of copper. At a 
high heat silver burns with vivid scintillations of a greenish- 
white color. It volatilizes at a high heat, and therefore, when 
melted in a crucible large globules of metallic silver are ob¬ 
served adhering to the cover. Its volatility is considerably 
increased in a current of gas, and it is rapidly volatile in the 
flame of the oxyhydrogen blowpipe. Where silver is refined on 
a large scale, arrangements are made to save that which would 

* Latin, argentum. 


294. Write the sp. gr., com. num. and sym. of silver. Whence is most of 
the silver of commerce obtained ? What other sources of silver are mentioned ? 
Mention some of the properties of this metal. What is the cause of the granu¬ 
lar appearance of silver'when hastily cooled ? How is the tarnishing of silver 



208 


ELEMENTS OF CHEMISTRY. 


otherwise be lost by volatilization. Tarnished silver is pro¬ 
duced by the action of sulphuretted hydrogen, as this metal 
has a great attraction for sulphur, which it takes from the 
sulphuretted hydrogen, forming sulphuret of silver. When 
heated with fusible siliceous matter, as glass, &c., silver oxi¬ 
dizes and stains the glass yellow or orange. This is owing to 
the formation of a yellow silicate of silver within the glass. 

Silver is not acted on even at a red heat by caustic alkalies. 
Crucibles of this metal are, therefore, used in chemical analy¬ 
sis, where it is necessary to employ the caustic alkalies, which 
at a red heat act on platinum crucibles. The only pure acids 
that act on silver are sulphuric and nitric, and by sulphuric 
acid it is not attacked until heat is applied. Nitric acid is the 
proper solvent of silver, and its solution furnishes tabular crys¬ 
tals of nitrate of silver. If any gold is contained in the silver, 
it is left undissolved as a brown powder. If, however, the 
gold exists in a greater proportion than -§• or J, it protects the 
silver from the action of the nitric acid. Hence, it is impos¬ 
sible to reduce by nitric acid an alloy containing this amount 
of gold. A mixture of 8 sulphuric acid and 1 nitre, will dis¬ 
solve silver when alloyed with or covering copper, without 
dissolving the copper. Hence, this mixture is used to remove 
the silver from old plated ware and from silver coins. 

For coinage, and other economical uses, it is necessary to 
alloy silver with about T * F copper, to render it sufficiently stiff 
and hard. To determine the proportion of pure silver, the 
coin may be dissolved in nitric acid, and muriatic acid or a 
solution of common salt added, which precipitates chloride of 
silver. This precipitate is so bulky and insoluble in water as 
to impart a cloudiness to a solution of silver diluted a million 
fold. The amount of precipitate formed will depend upon the 
amount of silver which the solution contains, and will there¬ 
fore determine its proportion. As in this experiment hydro¬ 
chloric acid or chloride of sodium is used to test for silver, so 
nitrate of silver (295.) is often used in testing for chlorine in 
water. This may be illustrated by adding a little salt (chlo¬ 
ride of sodium) to a glass of water. When the salt is dis¬ 
solved, add a little nitrate of silver, and a white cloudy pre¬ 
cipitate of chloride of silver is instantly formed. Every hun- 


generally produced ? What color does oxide of silver give to glass ? When 
gold and silver are alloyed, by what acid may they be separated 1 What is 
the effect of a large proportion of gold in this alloy ? What mixture is used 
to dissolve silver when alloyed with or covering copper ? What metal is al¬ 
loyed with silver in coinage ? How may the proportion of pure silver in coin 
be determined ? What salt of silver is used as a test for chlorine ? By what 
experiment is this illustrated ? Explain the process by which silver is obtained 



THE ELEMENTS AND THEIR COMBINATIONS. 209 

dred grains of this precipitate indicate 42 grains of common 
salt. Silver is obtained from one of its ores, the sulphuret, on 
the same principle. This ore is first converted into a chloride 
of silver, and then reduced from this state to metallic silver. 
The process is as follows : Common salt is added to the ore, 
and the whole roasted in a furnace. By this means the sul¬ 
phur is expelled, and the chlorine of the chloride of sodium 
unites with the silver, forming chloride of diver. This is then 
put into barrels which revolve on an axis ; water is added with 
oxide of iron and metallic antimony. The whole is agitated 
for some time, during which the iron takes the chlorine from 
the chloride of silver, and reduces the metal. A certain pro¬ 
portion of mercury is then introduced and agitated with the 
reduced silver. This the mercury dissolves out together with 
the gold, if there be any, metallic copper, and other substances, 
forming a fluid amalgam easily separable from the thin mud 
of earthy matter by subsidence and washing. This amalgam 
is strained through a strong linen cloth, and the solid portion 
exposed to heat, by which the remaining mercury is volatilized 
and the silver is left behind in an impure condition. It is 
afterwards rendered pure by various processes acccording to 
the nature of the substances it is supposed to contain. 

A different process is usually employed to obtain silver from 
galena. The process employed in this case is called cupella- 
tion. The galena is pulverized and placed with’ a certain 
quantity of metallic lead on a little 
thick cup or cupel, a , Fig. 85. This 
cupel, which is made of bone-ashes, 
is placed in a muffle, b, and the 
whole is exposed to high heat and a 
current of air, which oxidizes the 
lead. One portion of the oxide of 
another is absorbed by the cupel, and carries down with it the 
other impurities, leaving the silver in a brilliant metallic 
button. As the coating of oxide of lead becomes thin, the sil¬ 
ver presents the colors of the rainbow, and the instant that the 
whole is absorbed, the silver becomes excessively brilliant. 
This peculiar effect is called figuration, and only takes place 
the instant the metal has become pure. 

When this process is to be performed on a large scale, the 
galena is reduced, by roasting and smelting with charcoal, to 
metafile lead, in which the silver also is contained. This 


Fig. 85. 



lead escapes in vapor , 


from the sulphuret of silver. Explain Fig. 85. How is cupellation performed 
on a large scale. 






210 


ELEMENTS OF CHEMISTRY. 


mass is then put into a kind of reverberatory furnace, called 
the refining hearth, which is hollowed out like a kettle. On 
this hearth it is heated for a day, while a constant current of 
air is passed over the metal, until all the lead is at last con¬ 
verted into oxide. This oxide melts in the heat, and partly 
flows off as litharge through a tube, and partly soaks into the 
porous mixture of clay and lime which has been firmly beaten 
down on the hearth of the furnace. The silver remains behind 
in the metallic state. This is rendered still purer by a second 
heating in clay-basins (smaller cupels), which absorbs the re¬ 
mainder of the litharge. If other metals are present in the 
silver ore, they are likewise oxidized and carried down into the 
cupel by the litharge. 

Many of the copper ores also contain silver. These ores are 
calcined and mixed with a large proportion of lead and then 
fused and run into moulds. In this form they are called liqua¬ 
tion cakes. These are placed with layers of charcoal upon an 
inclined hearth. When the coal is ignited the heat is sufficient 
to melt the lead but not the copper; the lead, therefore, flows 
off, and carries with it the silver, while the copper remains 
behind. The mixture of lead and silver is converted into me¬ 
tallic silver and oxide of lead by cupellation. This process, as 
well as the last, is much facilitated by the fact that the alloy 
of silver and lead is more fusible than pure .lead. By cooling, 
therefore, the latter separates from the melted alloy, which is 
then drawn off. This small portion is cupelled, while the 
great bulk of the lead is removed for its ordinary uses. 

295. Nitrate of silver, AgO, NO s , crystallizes in colorless, 
transparent anhydrous tables, which are soluble in an equal 
weight of cold and in half their weight of boiling water. They 
are soluble also in alcohol. Nitrate of silver blackens when 
exposed to the light, if organic matter be present. It is, there¬ 
fore, frequently employed to dye the hair black, and also bones 
and ivory, as in chess-men and similar articles, to which it 
communicates an indelible stain. It also enters into the com¬ 
position of indelible ink. The linen to be marked is previous¬ 
ly prepared by an application of solution of carbonate of soda 
and starch or. gum. Letters are then formed from a solution 
of 2 drams of nitrate of silver in an ounce of water, and India 
ink sufficient to give it the right color. These letters when 
dry areindelible. This stain is probably metallic silver, which 
in a state of minute subdivision is black. When ivory is sil- 


295. Write the symbol of nitrate of silver. What is said of the crystals of 
this salt ? Mention some of the properties of nitrate of silver. State some of 
the uses to which this salt is applied. 



THE ELEMENTS AND THEIR COMBINATIONS. 


211 


vered, it is immersed in a dilute solution of nitrate of silver, 
and left till it has become yellow. It is then taken out and 
put into a glass of distilled water, and exposed for a short time 
to the direct rays of the sun. It soon becomes intensely black. 
It is now taken out of the water and wiped dry. Finally, it 
is rubbed with leather. The silver is now on the ivory in a 
metallic state, and may be polished. White marble is figured 
on the same principle. The surface of the marble is covered 
with a very thin coating of wax. Through this waxen ground 
figures or writing are made, and when the marble is made 
bare in these lines, it is painted over with a camel’s-hair brush 
dipped in nitrate of silver. It is afterwards exposed to a strong 
sunlight, which decomposes the nitrate of silver, and produces 
a black stain on the marble wherever the salt touches. If two 
or three coatings of silver have been thus applied, the reduced 
silver will take a fine polish. The waxen ground is afterwards 
dissolved off by spirits of turpentine. 

296. Daguerreotype plates are copper plates, one surface of 
which is coated with silver. Oxide of silver is precipitated 
from a solution of the nitrate by potash. This precipitate is 
then filtered, washed, and dried, and finally dissolved in am¬ 
monia. In the solution thus prepared the copper plate is im¬ 
mersed, after being on one side varnished or otherwise protec¬ 
ted. The other side becomes coated with the oxide of silver 
precipitated from the ammoniacal solution. It is then removed 
from the solution and the ammonia allowed to evaporate. 
When quite dry, the plate is held over a charcoal fire by the 
heat from which the oxide of silver is decomposed,* and the 
metal reduced on the copper in the form of a complete coating. 
This may be made beautifully bright by polishing with leather 
and polishing powder, and the plates prepared in this way 
afford the best surfaces for Daguerreotype pictures. 

Clock-faces and barometer plates are silvered in a similar 
manner. The mixture for this purpose consists of muriate of 
silver (297.) and moistened cream of tartar. This is rubbed 
over the plate until it has acquired a complete coat of silver. 
The cream of tartar^ (acid tartrate of potash) cleans and 

* The oxides of the following metals are also reduced by heat; gold, mer¬ 
cury, silver, platinum, palladium, iridium, and rhodium. Hence, these are 
called noble melals, as they are less easily oxidized than the other metals, and 
more easily restored to their metallic state. For this reason, these metals are 
often classified together. 


296. How are daguerreotype plates prepared ? How are clock-faces and 
barometers silvered ? How may a silver tree be made 1 In what form is ni¬ 
trate of silver used in medicine ? 




212 


ELEMENTS OF CHEMISTRY. 


brightens the surface, and thus prepares it for receiving the 
silver. The plate is frequently heated and immersed in dis¬ 
tilled water, to wash off the superfluous saline matter. 

A silver tree (see Fig. 83.) may be made by pouring into a 
glass globe or decanter, £ oz. of nitrate of silver dissolved in 
about a pint of distilled water. Add \ oz. of mercury, and in 
a short time the silver will be precipitated in the most beauti¬ 
ful arborescent form, which is therefore called Arbor Diana, 
or Tree of Diana. In this case, the nitric acid of the nitrate 
of silver has a greater affinity for the mercury than it has for 
the silver; it therefore deposits the silver and dissolves the 
mercury. If upon a plate of polished copper, several drops of 
nitrate of silver be let fall, in a short time a very beautiful 
precipitate of metallic silver will take place in the arborescent 
form. 

The solid nitrate of silver is melted and cast into sticks or 
quills. In this form it is called lunar caustic , and is used in 
surgery as a caustic. 

297. Chloride of silver , AgCl. The method by which this 
salt is prepared has already been mentioned (294.) It is quite 
insoluble in water and nitric acid, and but slightly dissolved by 
a large quantity of hydrochloric acid. When heated it melts, 
and on cooling becomes a grayish, crystalline mass, which cuts 
like horn ; hence, when found native, this is called horn-silver 
(289.). It may be reduced by fusion with twice its weight of 
carbonate of soda or potash. It is decomposed by light, both 
in the dry and wet state : very slowly if pure, and quickly, if 
organic matter be present. Also in water with metallic zinc 
or iron it is reduced, especially if sulphuric acid be added to 
generate hydrogen. It is soluble with great ease in ammonia. 
The artificial yellow diamond is made by coloring white 'paste 
(see experiments on silica), with the chloride of silver, and ex¬ 
posing the whole to a furnace heat. 

298. Fulminating silver , is a terribly explosive compound. 
It explodes by the heat of the hand, by the touch of a tube, 
and sometimes by a feather. It even explodes sometimes under 
the fluid in which it is formed, and of course, while still wet. 
It is formed by adding to a solution of nitrate of silver a solu¬ 
tion of pure lime, as long as a precipitate of the oxide of silver 
occurs. The liquid is then filtered off, and the precipitate 
washed with warm water. The powder thus formed is put 


297. Write the symbol of chloride of silver. Mention some 'of the properties 
of this salt. What color does this substance impart to glass ? 

298. What is said of fulminating silver ? How is it prepared ? To what is 
the violent and sudden explosion of the fulminates owing ? 



THE ELEMENTS AND THEIR COMBINATIONS. 


213 


into a warm place upon paper, that it may he well dried, and 
when dry, it is put into a wide mouthed phial, containing" pure 
liquid ammonia. The phial is then corked and allowed to re¬ 
main a whole day, or until the powder becomes black. By 
this process the powder becomes explosive. The liquid is then 
poured oft and the phial left open in a place where the heat is 
not greater than 80° or 100°. When dry, this powder should 
remain undisturbed in the phial, as the least friction will cause 
the whole mass to explode. A watch crystal would answer 
better for drying the fulminating powder, both on account of 
the wide surface exposed, and the greater ease with which the 
powder may be removed when dry. Less injury is done if an 
explosion occurs. 

A similar fulminating powder of gold and platinum may be 
formed (316 and 322.) The violent and sudden decomposition 
of these bodies is owing to the feeble attraction which exists 
between the constituents of the substance, viz : between the 
oxide of the metal and the ammonia, while the affinity of the 
oxygen of the oxide and the hydrogen of the ammonia is very 
powerful.' In the explosion, therefore, the metal is reduced, 
water formed, and nitrogen evolved. 

299. Soluble salts of silver are easily known from the white, 
curdy precipitate of chloride of silver, which darkens by expo¬ 
sure to light, and is insoluble in hot nitric acid. This precipi¬ 
tate is produced by the addition of a soluble chloride of any 
other base. The chloride of lead, and the protochloride of 
mercury, are precipitated in a similar way, but the latter is 
easily determined by the tests for mercury, and chloride of lead 
is soluble to a great extent in boiling water. Solutions of silver 
are reduced to the metallic state by iron, copper, mercury, and 
other metals. 


GROUP SIXTH. 

Tin, 7. 59. Sn* 

300. Tin is one of the few metals which were known in 
the most ancient times. As its ores are .often found in the 
sand by which the soil is covered, it was, therefore, easily ob- 
* Latin, stannum. 

299. Mention some of the tests for silver. How do the metals of this group 

differ from those of the preceding groups ? How do the oxides and sulphurets 
of these metals differ from those of the next group ? . 

300. Write the sp. gr., com. nutn., and sym. of tm. What is said ot this 





214 


ELEMENTS OF CHEMISTRY. 


tained. It is also a metal easily smelted. Formerly it was 
procured principally from the British Islands, and even now 
these islands, with Malacca, in the I^ast Indies, furnish the 
purest tin. 

The properties which especially characterize tin, and render 
it a valuable metal, are, its beautiful lustre, its great softness 
and flexibility, its slight affinity for oxygen, in consequence of 
which it long retains its brightness in air and water,* its easy 
fusibility (melting point, 442°,) which renders it peculiarly 
well adapted for casting and for coating other metals. It is 
very malleable, and hence it is beaten out into tin-foil. Spuri¬ 
ous silver-leaf is made of an alloy of tin and zinc, which is 
hammered out into extremely thin leaves. When bent, tin 
emits a peculiar crackling sound, which is called the “ cry of 
tin.” When heated above its melting point, it oxidizes rap¬ 
idly, and becomes converted into a whitish powder used in the 
arts for polishing, under the name of putty powder. The 
common putty used for setting glass, is a compound of carbonate 
of lime and linseed oil. Tin is easily attacked by hydrochloric 
acid with the evolution of hydrogen, and with nitric acid the 
action is very energetic, producing a white hydrate of the per¬ 
oxide. It is one of the best conductors of heat and electricity. 

In reducing tin from its ore, this is first broken down and 
roasted, to drive off arsenic and to oxidize the iron which it 
usually contains. It is then washed or elutriated with water, 
by which process the lighter particles of stone, and to a great 
extent also, the oxide of iron, are washed away. Finally, it is 
fused with charcoal in a blast-furnace, and carbonic oxide and 
metallic tin are obtained ; the latter flows off below. Some 
lead is added to tin for common tin-plate, because pure tin is 
somewhat brittle and does not adapt itself well to the moulds. 
In many countries the quantity of lead to be added is Regulated 
by law (i to f). An alloy of this kind is called proof-tin, to 
distinguish it from grain-tin , which is tin in its greatest purity. 

Tin plate may be beautifully crystallized by heating the 
plate till the tin is melted, plunging it while hot in water, and 
finally rubbing it alternately with paper balls, one moistened 

* This metal, with antimony, arsenic, and chromium, are often arranged into 
a class next to the noble metals, as their oxides easily lose their oxygen, or form 
weak bases or acids. 


metal ? Mention some of its properties. State the process by which this metal 
is obtained from its ore. How may tin-plate be crystallized ? What is the 
composition of speculum-metal ?—pewter ?—tin plate ? For what purpose is 
tin used in bell-rnetal 1 State the composition of mosaic gold. What effects 
are produced by tin on the system 1 Mention the tests for tin. 



THE ELEMENTS AND THEIR COMBINATIONS. 


215 


with dilute aqua-regia, and another with caustic potassa. 
Both these liquids dissolve the coating of oxide, and lay bare 
the pure metallic tin surface. 

Speculum-metal , a brilliant, almost white, excessively brit¬ 
tle alloy, consists of tin 2, copper 5 parts. When hardened by 
the admixture of antimony, &c., tin forms pewter. Tin plate 
is sheet iron coated with tin, and copper vessels are often coated 
with tin on the interior surface to prevent the corrosion of 
vegetable, acids. The use of tin in bell-metal (278.) is to render 
the copper more fluid, and to cause it to assume more perfectly 
the impression of the mould, as well as to render it more sonor¬ 
ous. Mosaic gold (aurum musivum), consists of sulphuret of 
tin 2, and sal ammoniac 1 part. The sulphuret of tin for this 
purpose, is formed by’'combining white oxide of tin with sul¬ 
phur. Mosaic gold is used by artists to give a beautiful color 
to bronze. 

Tin is not so poisonous as lead or copper, but it is still in¬ 
jurious to health. Acid food and drinks should not be allowed 
to stand for any considerable length of time in tin or in tinned 
vessels. 

The tests for tin are chloride of gold, which produces a pur¬ 
ple precipitate, chloride of platinum, an orange, ferrocyanide of 
potassium, white, corrosive sublimate, black, a plate of lead 
which precipitates metallic tin. 

Antimony, 7. 65. Sb.* 

301. This metal is derived chiefly from its native sulphuret, 
which is a rather abundant mineral. The ore is freed from 
earthy impurities by fusion,- and is afterwards decomposed by 
heating with metallic iron or carbonate of potash, which re¬ 
tains the sulphur. On cooling, the heavy metallic antimony 
settles to the bottom. 

Antimony has a lamellar, crystalline texture, and tin-white 
color, like bismuth, but without its red tint. It has a high 
lustre. It is not very hard, but exceedingly brittle and easily 
reduced to powder. It fuses at 810.° Out of contact of air it 
volatilizes only at very elevated temperatures, but in a current 
„pf air much less heat is required. In a current of hydrogen 
gas it may be distilled at a white heat, but when covered with 
a flux, it does not lose more than °f weight at the 

* Latin, stibium. 


301. Write the sp. gr., com. num., and sym. of antimony. What is the prin¬ 
cipal source of this metal 1 Mention some of its properties 1 What is said of 
the alloys of antimony ? State the composition of type-metal.—white-metal. 



216 


ELEMENTS OF CHEMISTRY. 


strongest white heat. It is not oxidized by the air at common 
temperatures, but when heated to a white heat in a covered 
crucible, and then suddenly exposed to the air, it inflames and 
burns with a white light. The oxide produced during this 
combustion, is often deposited in beautiful crystals, in the form 
of small shining needles, of silvery whiteness. By hot hydro¬ 
chloric acid antimony is dissolved with evolution of hydrogen, 
and chloride of antimony is formed. Nitric acid oxidizes it to 
an insoluble white antimonic acid. 

Antimony forms brittle alloys with some of the malleable 
metals. When gold is alloyed with of antimony, the com¬ 
pound is brittle. Even the fumes of antimony in the vicinity 
of gold render it brittle. The most important of the alloys of 
antimony is type-metal. This is composed of antimony 1, lead 
8 to 16, and a small addition of copper. Lead alone is much 
too soft to be employed for this purpose, but alloyed with anti¬ 
mony it acquires ^uch a degree of hardness, that types cast 
from it may be used for printing many thousand times without 
losing their distinctness. Type-metal expands in the act of 
solidifying, and therefore takes an accurate impression of the 
mould. White-metal spoons are formed of tin 100, antimony 
8, bismuth 2, and copper 2. 

302. Sulphuret of antimony , crude antimony, SbS 3 , is a lead- 
gray, brittle substance, having a radiated crystalline texture. 
It melts even in the flame of a candle, and hence, may be 
easily obtained from the various rocks with which it is associ¬ 
ated. On solidifying after fusion, it becomes filled with cracks, 
owing to its great contraction. At a strong red heat it boils, 
and may be distilled without decomposition if the air be ex¬ 
cluded. It is sometimes prepared by precipitating a solution 
of tartar emetic (tartrate of antimony and potash,) with sul¬ 
phuretted hydrogen. In this case, a sulphuret of potash is also 
formed, which being soluble, remains in the solution, while the 
sulphuret of antimony, being insoluble, is precipitated. As 
thus prepared, the sulphuret of antimony has an orange color , 
which grows darker on drying. It is also prepared by melting 
together antimony and sulphur. Mixed with nitre, &c., it is 
easily burnt, and gives a bright white or bluish-white flame. 
It is, therefore, much used in pyrotechnic compositions. 

The soluble compounds of antimony are hostile to life, and 
the stomach exerts itself to remove all such compounds intro- 


302. Write the symbol of sulphuret of antimony. Mention its properties. 
What is its color when precipitated from solution of tartar emetic by sulphu¬ 
retted hydrogen ? For what purpose is it sometimes employed ? What 
are the relations of antimony to medicine ? Mention the tests for antimony. 



THE ELEMENTS AND THEIR COMBINATIONS. 


217 


duced into it. This is effected by vomiting, and for its use in 
producing this action of the stomach, antimony has become an 
important medicine. 

The tests for antimony are sulphuretted hydrogen, which 
gives an orange precipitate, and a plate of iron which precipi¬ 
tates metallic antimony in the form of a black powder. 

Arsenic, 6. 75. As. 

303. Metallic arsenic is found native in thick crusts called 
testaceous arsenic, evidently deposited from sublimation. Most 
of this metal, however, is derived from roasting the native 
arseniuret of iron, nickel, and cobalt. The vapors of arsenious 
acid (304.) given out, are condensed in a long and nearly 
horizontal chimney, or in a kind of tower of brick-work, divided 
into numerous chambers. The crude arsenious acid thus pro¬ 
duced is purified by sublimation, and then heated with char¬ 
coal in a retort. The charcoal absorbs the oxygen of the 
acid, and reduces metallic arsenic which sublimes. 

Arsenic is a soft, brittle, exceedingly poisonous metal. Its 
color is tin-white, inclining to a steel-gray. It has a high 
metallic lustre, and is easily crystallized. When heated it 
volatilizes without fusion, and, if air be present, oxidizes to 
arsenious acid. This vapor has the smell of garlic. Arsenic 
combines with the metals in the same manner as sulphur and 
phosphorus, which it resembles, especially the latter, in many 
respects. The combustion of arsenic may be performed by 
throwing a few grains in powder into a red-hot crucible. It 
bursts into a flame of a bright blue color, and continues to 
burn until completely consumed or volatilized. 

304. Arsenious acid , white oxide of arse?iic, As0 3 . As com¬ 
monly obtained, this is a white, glassy-looking substance in 
brittle masses, with a conchoidal fracture, and shows marks 
of fusion. When freshly prepared it is transparent, but by keep¬ 
ing, it becomes opaque, and acquires a greater degree of solu¬ 
bility in water. 100 parts of water at 212° dissolve about 
11-5 parts of the opaque variety ; the larger portion separates 
on cooling, leaving about 3 parts dissolved. Cold water agi¬ 
tated with arsenious acid takes up a still smaller quantity. 
Alkalies dissolve this substance freely, forming arsenites which 
do not crystallize. Hydrochloric acid also readily dissolves it. 


303. Write the sp. gr., eom. num., and sym. of arsenic. How does this 
metal occur ? How is this metal usually obtained 1 Mention some of its prop- 

304. Write the symbol of arsenious acid. What are the properties of this 
substance ? What is the best antidote for arsenious acid ? In what state is 

10 




218 


ELEMENTS OF CHEMISTRY. 


Arsenious acid sublimes at 380°, and crystallizes on cooling, 
in brilliant, transparent octahedrons, which are very charac¬ 
teristic. They may be formed for experiment by heating a 
small quantity in a glass tube. Its vapor is colorless and in¬ 
odorous, but, if sublimed from charcoal, it gives the peculiar 
garlic odor of metallic arsenic, for the charcoal takes away the 
oxygen and reduces the arsenic to the metallic state. It is 
almost tasteless, with a faint sweetish flavor, which with its 
color renders it the more dangerous. Most of the metallic 
poisons give warning by their peculiar taste, but the appear¬ 
ance and taste of arsenious acid is that of a harmless substance. 
The best antidote for this poison is the hydrate of the red ox¬ 
ide of iron. This remedy is most active when recently pre¬ 
pared and in a gelatinous condition. It forms an insoluble 
arseniate of the protoxide of iron. Like most other poisonous 
substances, arsenious acid possesses remarkable antiseptic prop¬ 
erties. For this reason the bodies of those who have been 
poisoned by it are often preserved. In natural history it may 
be used for the same purposes as corrosive sublimate (290). 

To determine in supposed cases of poisoning, one of the best 
methods is that called Marsh’s test. Introduce into a small 
flask (Fig. 86,) some pieces of zinc and dilute sulphuric acid. 

Hydrogen will be formed which will escape 
through the bent tube c. After some time, if 
the jet of hydrogen be lighted, and a porcelain 
capsule held over the extremity of the flame, 
drops of pure water will collect on the bottom 
of the capsule. In this the capsule is not dis¬ 
colored. If now a drop or two of any arsenical 
solution be introduced into the flask, the flame, 
after the gas has been rekindled, will present a 
bluish-white appearance, and will deposit on the porcelain 
capsule a smooth black or brown spot (mirror of arsenic). This 
spot is metallic arsenic. The arsenic introduced within the 
flask combines with hydrogen, forming arseniuretted hydrogen , 
which escapes and burns. When this flame is cooled by the 
porcelain capsule, the metallic arsenic will not burn at the low 
temperature thus produced, and is, therefore, deposited on the 
capsule. Arseniuretted hydrogen is a most poisonous gas. Its 
fumes should therefore be avoided, as, in several instances, ex¬ 
perimenters have lost their lives by this gas. 

In cases of poisoning, the stomach and its contents are 


Fig. 86. 



this remedy most effective ? How does the red oxide of iron destroy the poi¬ 
sonous properties of arsenic ? What use is sometimes made of arsenic 1 .Ex- • 
plain Fig. 86. What process is followed in cases of poisoning to detect arsenic V 



THE ELEMENTS AND THEIR COMBINATIONS. 


219 


divided into small pieces, and the organic matter destroyed by 
adding hydrochloric acid and chlorate of potash, or by heating 
with sulphuric or strong nitric acid, till the mass begins to 
char, and then draining with water, and filtering the solution. 
The liquor obtained is subjected to Marsh’s test. If a black 
spot is produced, this will indicate arsenic in considerable 
quantity. If no spot on the porcelain is produced, the tube is 
then ignited by a spirit-lamp at the point c, and a black ring 
will be formed on the tube a little beyond this point, if arsenic 
be present. A black spot will also be produced if antimony is 
present in the solution, but the latter will remain unchanged 
when a solution of chloride of lime is applied, while the arsen¬ 
ical spots will be dissolved. The bent tube should be made 
of hard glass, without lead, in order to bear the heat required 
in this experiment. 

305. Arsenic acid , AsO s , is white and anhydrous. It melts 
at a low red heat, and after fusion it is colorless, transparent, 
and glassy. If too strongly heated, it is white and opaque. 
When put into water it slowly and completely dissolves, giving 
a highly acid solution, which deposits on evaporation hydrated 
crystals of arsenic acid. When strongly heated, it is decom¬ 
posed into arsenious acid and oxygen gas. It is excessively 
poisonous. 

306. There are two principal sulphur ets of arsenic : Real¬ 
gar , AsS 2 , occurs native, and is formed artificially by heating 
arsenious acid with a minimum of sulphur. It has a splendid 
red color, is fusible and volatile, and is employed by the pyro¬ 
technist in making white fire. Orpiment , AsS 3 , is also a 
natural product, and is made by fusing arsenious acid with an 
excess of sulphur, and by precipitation with sulphuretted hy¬ 
drogen from a solution of the acid. It is a golden-yellow crys¬ 
talline substance, fusible and volatile by heat. In acid solu¬ 
tions of arsenic, sulphuretted hydrogen produces a splendid 
yellow precipitate of sulpharsenious acid. Heat promotes the 
separation of this precipitate. 

Gold, 19'5. 99. Au.* 

307. Gold, in small quantities, is a very diffused metal; 
traces of it are constantly found in the iron pyrites of the most 

*-Latin, aurum. 


305 . Write the composition of arsenic acid. How is this substance formed ? 
Mention some of its properties. 

306 . Write the composition of realgar. How is it prepared ? What are its 
properties ? - Write the composition of orpiment. How is this substance pro¬ 
cured ? State its properties. 



220 


ELEMENTS OF CHEMISTRY. 


ancient rocks. It is always met with in the metallic state, 
sometimes beautifully crystallized in the cubic form, associated 
with quartz, oxide of iron, and other substances, in regular 
mineral veins. The sands of various rivers have long fur¬ 
nished gold, derived from the crumbling down of rock. Some 
crystals of native gold from California, are represented in the 
accompanying figures. In Figs. 88 and 89, is also seen the 
native gold attached to the crystals, 


Fig. 87. Fig. 88. 



Fig. 89. 



in the form in which it usually occurs. Gold ore is crushed 
and shaken in a suitable apparatus with water and mercury ; 
the mercury forms an amalgam with the gold, which is sepa¬ 
rated and afterwards exposed to heat, by which the mercury 
is distilled, and pure gold left behind. 

To obtain gold from its alloy of silver and copper, it is boiled 
with concentrated sulphuric acid, which dissolves the silver 
and copper, and leaves the gold as a brown powder. The 
gold being separated, the silver is afterwards obtained from 
the acid solution by adding more copper. The greater affinity 
of the acid for the copper causes it, when saturated with this 
metal, to leave the silver, which is therefore precipitated. 
Copper alone remains in the solution, which is poured off and 
evaporated to form sulphate of copper or blue vitriol. 

Pure gold is obtained by solution in aqua-regia and precipi¬ 
tation by a salt of the protoxide of iron, which takes the oxy¬ 
gen from the solution of gold, and reduces the gold to the me¬ 
tallic state. The gold falls down in brown powder, and ac¬ 
quires the metallic lustre by friction. 

308. From all other metals gold is distinguished by its yel- 
low color, and its extreme permanence in air and fire. Even 
sea-water, which corrodes silver, has no action on gold. Hence, 
mirrors for light-houses are often coated with a thin film of 


307. Write the sp. gr., com. num., and sym. of gold. What is said of this 
metal ? How is gold obtained 1 How is it obtained in a pure state 1 






THE ELEMENTS AND THEIR COMBINATIONS. 


221 


gold to protect them from the action of the sea-air. When 
heated in common furnaces gold is not sensibly volatile, hut it 
volatilizes in a very hot furnace, under the flame of the oxyhy- 
drogen blowpipe, or when exposed in very fine leaves to the 
action of a strong galvanic battery. It is volatilized also when 
the charge of a powerful electrical battery is passed through a 
fine wire or leaf of gold. If the discharge takes place over a 
silver plate, the latter is gilded with the volatilized and subse¬ 
quently condensed gold. If the gold is volatilized a little dis¬ 
tance above a sheet of paper, this receives a purple-brown color, 
from the deposit of gold in a minute state of division. Gold, 
is distinguished also by its great malleability, which is such 
that gold leaf not more than °f an ma Y 

beaten out, and a single grain of gold may be extended over 
156 sq. in. of surface. So great is its ductility , that a grain 
of gold may be drawn out into 500 feet of wire, and one 
ounce of gold may be extended 300 miles. Its density is also 
more than twice that of iron or copper, and nearly twice that 
of lead. Alkalies, either caustic or carbonated, at the com¬ 
mon temperature do not attack gold ; when, however, they are 
heated with this metal in contact with air, an oxide of 
gold is formed, with which they unite, forming an alkaline 
aurate. The acids separately do not attack gold (except se- 
lenic acid), but aqua-regia dissolves it readily. In this case 
the active agent is -chlorine, which exists in a free state in 
this acid mixture. Solutions of gold are decomposed by hydro¬ 
gen and sulphurous acid gas. These gases take the oxygen 
from the oxide of gold in solution, and liberate the gold in the 
metallic state. There are two oxides of gold, both of which 
refuse to unite with acids. With chlorine, iodine, sulphur, &c., 
gold forms two- compounds corresponding to those with oxygen. 
The affinity of gold for oxygen is so weak that solutions of the 
oxide are decomposed even by light. 

Gold melts at 2016°, and, when in fusion, appears of a 
bright green color. This color is nearly the same that it has 
when a thin leaf of gold is held up to the light, or when an 
eleatrical spark is passed over a strip of gold leaf in a dark 
room. When intensely ignited by electricity, or the oxy- 
hydrogen blowpipe, gold bums with a greenish-blue flame. 


The alloys which gold forms with other metals are remarkable chiefly 
for the opposition of their properties to those of their constituent metals. 
With lead the compound is very brittle, even when the lead constitutes 


308. How is it distinguished 
erties of gold are mentioned ? 


from all the other metals ? What other prop- 
What is said of the compounds of gold 1 




222 


ELEMENTS OF CHEMISTRY. 


but the JY20 P art of the all°y. Even the fumes of lead destroy the 
ductility of gold. With zinc the compound is brittle and of the color 
of brass. The fumes of zinc in a furnace containing fused gold make it 
brittle. With tin it forms a whitish alloy, brittle when thick (if the 
proportion of tin is greater than ^~), but flexible in thin plates. With 
platinum it forms an alloy soluble in nitric acid, which is not the case 
with either gold or platinum by themselves. One part of platinum is 
sufficient to render the alloy, with ten parts of gold, white, and of its 
own color. With copper (forming standard gold) the alloy is perfectly 
ductile and malleable, but harder than pure gold, and resists wear better 
than any other alloy, except that with silver. The alloy of gold and 
iron is malleable and ductile. It is harder than gold, and of a dull white 
color. In this the metals expand by union, while in the alloy with zinc 
they contract. 

309. Fulminating gold is prepared by adding ammonia in 
excess to a concentrated solution of sesquichloride of gold/ 
diluted with about three parts of water. A yellowish brown 
precipitate is formed, which is collected upon a filter, and care¬ 
fully dried at the temperature of boiling water. This when 
dry explodes with terrible violence, but it requires a higher 
heat (120° to 300°), or a greater degree of friction than fulmi¬ 
nating silver. If placed upon a piece of sheet copper, and held 
over a lamp, it will soon explode, and the copper, if not torn, 
is always indented. Fulminating gold consists of 1 sesqui- 
oxide of gold, (Au 2 0 3 ), 2 ammonia (2NH 3 ), and water (HO). 

310. Gilding on copper is performed by dipping the arti¬ 
cle into a solution of nitrate of mercury, and then rubbing it 
with a soft amalgam of gold and mercury. It is then heated 
to expel the mercury, and burnished. Gilding on iron and 
steel is done either by applying a solution of perchloride of gold 
ill ether, by first galvanizing the iron with zinc, or by roughen¬ 
ing the surface of the metal, heating it, and applying gold leaf 
with a burnisher. Gilding on wood , Spc., is done by painting 
the design to be gilded with varnish, and then applying gold 
leaf. After the varnish is dry, the gold leaf is rubbed off, ex¬ 
cept where it was made to adhere by the varnish. Gilding by 
the galvanic process (p. 54,) is now rapidly superseding many 
of the other processes. Gold wash is a mixture of the oxide 
of gold with carbonate of soda or potash in excess. Articles 
cleansed with nitric acid are boiled in this wash, and thus be¬ 
come perfectly covered with a thin film of gold. 

The most simple mode of testing gold, is to rub some of it 
off upon a black-flint slate (touch-stone), and apply to the 


309. How is fulminating gold prepared ? What are its properties ? 

310. State the process for gilding on copper;—on steel;—on wood. What 
process is now generally preferred in gilding 1 State the composition and mode 
of using gold wash. Mention some of the tests of gold. 



THE ELEMENTS AND THEIR COMBINATIONS. 


223 


mark nitric acid. If the gold is pure, the yellow streak re¬ 
mains unchanged ; but if alloyed, it partly disappears ; if only 
an imitation of gold, it dissolves entirely. The presence of gold 
in solution may be known by the brown precipitate of metallic 
gold with protosulphate of iron, which is fusible before the 
blowpipe into a bead. When added to a solution of proto¬ 
chloride of tin, a purple precipitate is formed, ( -purple of Cas¬ 
sius), which is a mixture of peroxide of tin and metallic gold 
(p. 215.) 

Platinum, 21.5. 99. Pt. 

oil. Crude platinum, a native alloy of platinum, palladium, 
rhodium, and a little iron, oceurs in small grains and rolled in 
masses, sometimes of considerable size. It is found on the 
slope of the Ural mountains, in Uussia, mixed with gravel and 
transported minerals. It also occurs in Ceylon, in California, 
and a few other places. It has never been seen in place (in 
the rock, or in the vein), but the rock to which it belongs is 
supposed to be serpentine. 

Platinum is a white metal, between tin and steel in color, 
and inferior to silver in lustre. When pure, it is a soft metal, 
but usually, owing to impurity, it is quite hard. A very little 
rhodium or iridium renders it more gray in color, and much 
harder. It is exceedingly malleable and ductile both hot 
and cold. It is very infusible, melting only by the oxy-hy- 
drogen blowpipe or the galvanic battery. Like gold, silver 
and iron, it admits of being welded at a high temperature, and 
in this way it is made into chemical vessels. It dissolves in 
aqua-regia, and superficially oxidizes with fused hydrate of 
potash, and the potash enters into combination with the oxide 
thus formed. All the easily fusible metals combine with pla¬ 
tinum, and the alloys which they form are quite fusible and 
easily attacked by acids ; hence platinum vessels are ruined 
when these alloys are formed. Platinum crucibles are also 
attacked at a red heat by copper and silver, and by a mixture 
of silica and carbon. The latter is a frequent cause of the 
destruction of platinum vessels, when heated in-charcoal fires. 
These vessels also should never be exposed to the action of 
chlorine, or its compounds, especially when chlorine is disen¬ 
gaged in its nascent state. It is in this state that chlorine 
renders aqua-regia a solvent for gold and platinum. 

312. Platinum is obtained pure by digesting crude platinum 

311. Write the sp. gr., com. num., and sym. of platinum. How does this 

metal occur ? Mention some of its properties ? What class of metals combine 
with platinum ? , . . . „ TT 

312. How is platinum obtained pure ? What is platinum sponge ? How 




224 


ELEMENTS OF CHEMISTRY. 


in aqua-regia, and adding to the deep brown liquid a solution 
of chloride of ammonium. This throws down an orange 
colored precipitate, which is a double chloride ot platinum and 
ammonium. When heated, the chloride of ammonium is 
driven off, and also the chlorine of the chloride of platinum, 
and the platinum reduced to the metallic form. In this state 
it is a dull brown mass called spongy platinum, or platinum 
sponge. This is condensed in steel moulds with heat and 
pressure to the metallic state, and when compact enough to 
bear the blows of a hammer, is heated and forged into a bar, 
which can afterwards be rolled into plates or drawn into wire 
at pleasure. 

Platinum sponge has the power of absorbing several of the 
gases, and when suspended in a jar of oxygen and hydrogen, it 
causes the immediate union of the two gases (Fig. 38.) A jet 
of hydrogen falling upon spongy platinum, will, by its rapid 
combination with oxygen of the air, ignite the platinum, and 
afterwards take fire. In the same manner, clean slips of pla¬ 
tinum foil, and even gold and palladium, will produce the 
union of oxygen and hydrogen. If into a dry phial of oxygen 
gas a piece of platinum sponge be dropped, and the phial be 
stopped and set aside for several days, the platinum sponge 
will absorb the oxygen, as may be shown by unstopping the 
phial beneath water, when the water will rush up into the 
phial and quite fill it. Platinum sponge will absorb 100 times 
its bulk of oxygen. 

Red hot platinum also decomposes oils, spirits, &c. For 
this reason a coil of platinum is used in the safety lamp (174.) 
If a coil of platinum be suspended, while red hot, in a wine 
glass containing a little alcohol or ether, it will continue to 
glow, from the action of the vapor which arises from the al¬ 
cohol or ether. The action is so energetic that frequently the 
vapor is set on fire. The same experiment may be tried over 
the wick of a spirit lamp. The lamp should be lighted at 
first, and blown out when the coil of platinum is ignited. The 
coil will continue to glow, after the lamp is extinguished, until 
the whole of the alcohol is exhausted. 

313. Platinum black is another form of platinum, possess¬ 
ing similar properties to spongy platinum, but in a higher de¬ 
gree. When the galvanic current is passed through a weak 


are bars of pure platinum made ? Mention some of the properties of platinum 
spongeplatinum foilred hot platinum. By what experiment is this prop¬ 
erty of platinum illustrated ? 

313. What is platinum black 1 In what galvanic battery are the plates pla¬ 
tinized ? r 




THE ELEMENTS AND THEIR COMBINATIONS. 225 

solution of chloride of platinum, a black powder of platinum 
appears at the negative pole. The silver plate in Smee’s 
battery (p. 56,) are platinized in this way. Platinum black 
and platinum sponge after a time become inactive. Their 
properties are restored by heating them for a short time with 
nitric acid, and afterwards calcining platinum sponge at low 
redness, and drying platinum black at a gentle heat. 

314. Bichloride of platinum, PtCl 2 , is always formed when 
platinum is dissolved in aqua-regia. The acid solution yields 
on evaporation to dryness, a red or brown residue, deliquescent 
and very soluble in both water and alcohol. The aqueous 
solution has a pure orange yellow tint. Bichloride of platinum 
combines to form double salts with a great variety of metallic 
chlorides. 

315. Fulminating platinum , is prepared in the same 
manner as fulminating gold, and possesses similar properties. 
If 2 or 3 grains of either of these fulminating powders be placed 
upon a cold fire-shovel, and the shovel be gradually heated 
over a slow fire, when the fulminating powder arrives at about 
400° of temperature, a most violent explosion will take place. 
This experiment should be performed in the open air, as the 
sudden concussion given to the air is very likely to throw 
down and destroy everything standing around. The person 
performing the experiment should retire to some distance after 
placing the shovel on the fire. 

316. Platinum is invaluable to the chemist for crucibles and 
other vessels exposed to a high heat, or to the action of acids. 
Large retorts or boilers are made of it, for the use of manufac¬ 
turers of sulphuric acid, which sometimes hold sixty or seventy 
gallons. In Russia it has been employed in coinage, for which 
it is well suited by its great density and hardness, but its value 
is so fluctuating that its use as currency has been abandoned. 
Its value is intermediate between that of gold and silver. 

The tests for platinum are the chlorides of potassium and 
ammonium. These produce yellow crystalline precipitates, 
which are insoluble in acids, but readily soluble in alkalies. 

The following table includes a list of all the metals. To 
the list are added the specific gravities, combining numbers, 
* symbols, and other important facts in regard to the individual, 
metals. The small figures annexed to the names of the metals 
denote the groups (195) to which they belong. 

314. Write the composition of bichloride of platinum. How is this substance 
prepared ? What are its properties ? 

315. How is fulminating platinum prepared T State the properties of this 
substance. 

316. What are some of the uses of platinum ?—its tests ? 

10 * 



226 


ELEMENTS OF CHEMISTRY, 


• 




( 

METALS. 

Sp. Gr. 

Com. Num. 

Sym. 


1. Potassium/ 1 ). 

0.865 

39.20 

K. 


2. Sodium/ 1 ). 

0.972 

22.98 

Na. 


3. Ammonium/ 1 ). 

• • • • 

18.06 

NIL. 


4. Lithium/ 1 ). 

.... 

6.43 

Li. 


5. Barium/2). 

4.00 

68.67 

Ba. 


6. Strontium/2). 

2f 

43.84 

Sr. 


7. Calcium/2). 

2f 

20.00 

Ca. 


8. Magnesium/ 2 ). 

1.87 

12.71 

Mg. 


9. Aluminum/3). 

2.60 

13.68 

Al. 


10. Glucinum, O). 


6.97 

Gl. 


11. Zirconium.! 3 ). 

.... 

33.60 

Zr. 


12. Thorium/ 3 ^. 

• • • • 

59.51 

Th. 


13. Yttrium/ 3 ). 

• • • • 

33.20 

Yt. 


14. Erbium/ 3 ). 

15. Terbium/ 3 ). 

• • • • 

• • • • 

Er. 


• • • • 

• • • • 

Tr. 


16. Cerium/ 3 . 

• • • • 

47.26 

Ce. 


17. Lanthanum,! 3 ). 

.... 

47.04 

La. 


18. Didymium/3) . 

.... 

49.90 

Di. 


19. Chronium/ 3 ) _,. 

5.90 

26.24 

Cr. 


20. Titanium/ 3 ) . 

5.28 

25.17 

Ti. 


21. Tellurium/ 3 ) . 

6.20 

64.25 

Te. 


22. Niobium/ 3 ) . 

• • • • 




23. Tantalum/ 3 ) . 

• . . . 

184.90 

Te. 


24. Manganese/ 4 ) . 

7.05 

27.57 

Mn. 


25. Iron/ 4 ) . 

7.80 

28.00 

Fe. 


26. Cobalt/ 4 ) . 

8.60 

29.52 

Co. 


27. Nickel/ 4 ) . 

8.279 

29.57 

Ni. 


28. Zinc/ 4 ) . 

6.86 

32.53 

' Zn. 


29. Uranium/ 4 ) . 


60.00 

U. 


30. Cadmium/ 5 ) . 

8.604 

55.74 

Cd. 


31. Lead/ 5 ) . 

11.445 

103.56 

Pb. 


32. Bismuth/ 5 ) . 

9.80 

106.40 

Bi. 


33. Copper/ 5 ) . 

8.895 

31.65 

Cu. 


34. Mercury/ 5 ) . 

13.596 

100.00 

Hg. 


35. Silver/ 5 ) . 

10.474 

108.00 

Ag. 


36. Osmium/ 5 ) . 

10 about 

99.53 

Os. 


37. Palladium/ 5 ) . 

11.30 

53.22 

Pd. 


38. Rhodium/ 5 ) . 

10.64 

52.17 

Rh. 


39. Tin/6) . 

7.285 

52.82 

Sn. 


40. Antimony/®) .. 

6.702 

64.52 

Sb. 


41. Fungs ten, (6). 

17.60 

92.00 

W. 


42. Molybdenum/ 6 ) . 

8.615 

47.12 

Mo. 


43. Vanadium,! 6 ) . 

• * . • 

68.46 

V. 


44. Gold/ 6 ) . 

19.258 

98.22 

Au. 


45. Platinum/ 6 ) . 

21 about 

98.56 

Pt. 


46. Iridium/®) . 

15.683 

98.66 

Ir. 


47. Arsenic/ 6 ) . 

5.75 

75.00 

As. 


48. Tellurium/ 6 ) . 

6.20 

64.25 

Te. 


49. Rutherium . 

8.60 

51.68 

Ru. 


50. Pelopium . 

51. Donarium . 

.... 

.... 


52. Aridium . 

• • • • 




53. llmenium . 





54. Norium . 


.... 


V 



* 

* 

* 

* 

* 

* 

* 


* 


* 


* 

* 

* 

•* 

* 

* 

* 

# 

* 


* 

* 

* 

* 

* 

* 


Bodies most Generally 

Distributed. 































































































THE ELEMENTS AND THEIR COMBINATIONS. 


227 


1. To this list of the metals which are most generally distributed over 
the surface of the globe we may add titanium and gold, which, in small 
quantities , are very generally distributed; also the following non-metallic 
bodies;—oxygen, hydrogen, nitrogen, carbon, sulphur, chlorine, phos¬ 
phorus, fluorine, and, in small quantities, bromine, iodine and selenium. 

2. To the metallic elements met with in mineral waters, may be added 
the following non-metallic bodies; oxygen, hydrogen, nitrogen, carbon, 
chlorine, sulphur, boron, phosphorus and fluorine. 

3. To the elements found native , or naturally in an uncombined state, 
may be added the non-metallic elements, oxygen, nitrogen carbon, sulphur 
and selenium. Though iron is here put down among the native radicals, 
there are but very few instances on record of its being found in the na¬ 
tive state. 

4. This list includes those metallic elements which enter most fre¬ 
quently into the composition of organic bodies. They are the same with 
those found in the first column, and the same additions from the class of 
non-metallic elements are to be made to this as to the first list, viz.;— 
oxygen, hydrogen, nitrogen, carbon, chlorine, sulphur, boron, phospho¬ 
rus and fluorine. From this it is evident, that, in their natural state, all 
soils contain the elements essential to organized existence. 


PART III. 

ORGANIC CHEMISTRY. 


317. This branch of chemistry has all the interest and nov¬ 
elty of another science. An agent hitherto not considered, 
the principle of life, controls or modifies to such a degree the 
laws, properties, and forms of matter, that the latter is the 
mere instrument of life, or the material out of which life pro¬ 
duces its grand results. Among the effects of this new agent, 
are the following : 

1. The products of life are remarkable for the great variety 
of compounds which a few elements produce. Carbon, hy¬ 
drogen, oxygen, and nitrogen, in organic chemistry, are both 
the foundation and the superstructure, while a few inorganic 
elements, which are essential to living beings, are like bolts 
to hold the fabric together. From these few elements, changes 
and compounds without number are produced by the principle 
of life. 


These four elements have powers of combination which are unpara- 
lelled by the combinations of any other bodies. . Thus the elements of 
suboxide of lead Pb 2 0 unite to form a second compound PbO, a third 
Pb 0 2 , and a fourth Pb 3 0 4 ; but the combinations of carbon and hydro¬ 
gen are innumerable. We find not only the series CH, CH 2 , Ac., but 
also C 3 H 2 , C4H4, Ac. The series C 5 H 4 , C 4 0 H 8 , C 15 H 13 , Ac., is 
also inexhaustible. We find also the series C 2 H, C 4 H 3 , Ac., besides 
many other compounds of carbon and hydrogen, not included in any of 
the above series. With nitrogen, hydrogen and oxygen, carbon has an 
endless range of affinities. C combines with N, N with H, and we have 
the compounds CNH, CNO, CHO, CHNO, Ac. 

2. Organic substances are also remarkable/or the complex¬ 
ity of their structure. The bodies hitherto described in inor¬ 
ganic chemistry, have been invariably made up of elements or 
pairs of elements. This system, called the binary* system, 
may be illustrated by the following example : 


Latin bis, twice. 


317. What is said of organic chemistry ? What new principle is here found 
What are the effects of this principle on matter ? For what are the product! 
of life remarkable ? What four substances compose, for the most part, or 
game bodies ? - r ’ 





ORGANIC CHEMISTRY. 


229 


Alum. 


Sulphate of Alumina. 


abed 


Alumina. 


a b 


Sulphuric Acid. 


Crystallized Alum. 

I 


abode 


Water. 


Sulphate of Potash. 

I 


Hydrogen. Oxygen, 


Potash. 

I 


cd 


Sulphuric Acid. 


"I 


uminium. Oxygen. Sulphur. Oxygen. Potassium. Oxygen. Sulphur. Oxygen. 


Five 'pairs, a , b , c, d, and e, make up the compound abode 
or crystallized alum. These pairs also unite with each other in 
such a manner as to preserve through every grade of combina¬ 
tion the relation of two bodies , or a pair of bodies. Thus a and 
b unite in ab , c and d in cd ; ab and cd unite in abed , and abed 
with the single pair e in abode , or crystallized alum. 

The plan on which organic substances are formed is strik¬ 
ingly different. The combination is not usually by pairs, but 
in compounds of three or four elements. These triple or quad¬ 
ruple compounds enter into combinations, and pass through 
decompositions, and through all the changes of the bodies to 
which they belong as one , or as simple bodies, and are, there¬ 
fore, called compound radicals. 

There are, however, many compound radicals which consist of only 
two elements, and the future progress of the science may lead to the 
discovery, that all the compound radicals hitherto supposed to consist 
of three or four elements, may be resolved into two. On the other hand, 
in inorganic chemistry compound radicals have been recently discovered, 
which also favors the conclusion that the mode of combinations in these 
two great departments of chemistry may eventually prove to be the same.* 

3. Organic bodies contain ivithin the7nselves causes for 
their own decomposition. The constituents of inorganic bodies 
are usually united by their most powerful affinities, and, there¬ 
fore, these bodies have considerable permanence. But the vital 
principle unites in organic bodies several elements into a com¬ 
pound, for which they have weak affinities, while for each 

* These explanations are in accordance with the radical theory, supported 
by Liebig, and a majority of other chemists, and adopted in this work. Re¬ 
cently, however, the so-called nucleus theory has been gaining ground. It 
was originally proposed by Laurent, and has since been extended by Gerbardt 
and others. The leading idea in this system is, that the character of organic 
compounds depends on the peculiar grouping of their elements, rather than 
on the nature of those elements themselves. 


In what otherrespect are organic substances remarkable ? Explain the diagram. 
What is the usual method of combination, by which organic bodies are 













230 


ELEMENTS OF CHEMISTRY. 


other their affinities are powerful. Thus carbon, oxygen, hy¬ 
drogen, and nitrogen, are united in organic bodies in one com¬ 
pound, but the separate affinities of oxygen for carbon (to form 
carbonic acid), oxygen for hydrogen (to form water), nitrogen 
and hydrogen (to form ammonia), are more powerful than 
those which these bodies possess for the general compound, or 
for the organic body. While these opposing forces remain ex¬ 
actly balanced, the compound is preserved, but the moment 
one of them, from some accidental cause, acquires a prepon¬ 
derance over the rest, the equilibrium is destroyed, and the 
compound breaks up into two or more bodies of simpler and 
more permanent constitution. Heat produces this result by 
exalting the attraction of oxygen for hydrogen and carbon ; 
hence almost all organic bodies are destroyed by a high tem¬ 
perature. Mere molecular disturbance will sometimes cause 
destruction when the instability is very great. 

4. Organic forms are produced by the development of mul¬ 
titudes of little cells , or membranous bladders , containing a 
fluid , while inorganic forms are produced by the laws of 
crystallization. 

The membrane which constitutes the cell-wall sometimes contains 
pores, through which fine particles of solid matter pass, but most of 
these membranes. permit only liquids, or bodies in perfect solution, to 
pass within the cell-wall. The latter class form the finest filters known, 
and have never appeared to possess pores, even under the most power¬ 
ful microscopes. Through these' membranes food is carried within the 
-cell for the nourishment of fresh cellules, each produced from a living 
'point or germ. 

The living cell is a wonderful agent in the great variety of effects 
which it produces, without any corresponding change in its form, in its 
chemical composition, in the food by which it is nourished, or in that 
from which it derives the materials for its products. In one case it de¬ 
composes carbonic acid, rejecting the oxygen and uniting the carbon to 
the elements of water; again it produces out of the constituents of the 
air the odors of flowers ; in a third case it converts the albumen of the 
blood into milk. In the simplest form of living being, as among the 
humblest cellular plants, a single cell constitutes the entire fabric. This 
cell grows from its germ, absorbs and assimilates nutriment. A part 
of this it converts into the substance of its own cell-wall, another portion 
it secretes into its cavity, and from a third produces the reproductive 
germs that are to continue the race. Having completed the preparation 
of these germs and reached its own term of life, it bursts and sets free 
j./ the included germs, every one of which repeats the same process. In 
the highest forms of vegetable life we find but a multiplication of similar 
cells, among which, as by a division of labor, the functions of the plant 
are so distributed, that, by the concurrent labors of all, a more complete 
and permanent effect may be produced. 


formed? What is meant by a compound radical ? What is the third pecu¬ 
liarity of organic bodies mentioned 7 How is this explained ? How are or- 



ORGANIC CHEMISTRY. 


231 


These cells possess different forms, according to their mode of growth. 
They are globular unless their form is modified by extraneous causes, 
or affected by unequal nutrition. If, by being developed in large quan¬ 
tities, and by continuing to grow,' they press against each other, they 
sometimes form, especially when all of the same size, regular dodecahe¬ 
drons. At other times they are elongated into elliptical or prismatic 
forms, often by the compression of adjoining cells, or by unequal nutri¬ 
tion, or by both these causes combined (337). 

Cellular agency is as universal in the animal as in the vegetable 
kingdom. Even horny substances consist of cells, which have been com¬ 
pressed, their liquid contents dried up, and plates generally produced 
adhering to one another in different ways. But by the application of 
liquids capable of penetrating the cell-wall, these plates may be, in almost 
all cases, converted into the most beautiful cells. 

Crystallizable substances are, however, found, in all animal and vege¬ 
table fluids. But in animals, both the large quantity of the dissolving 
liquid and its rapid circulation, prevent the deposition of these substances. 
No crystals or inorganic bodies are, therefore, found in the body when 
in a healthy state, except in the bones and the adjoining tissues, where 
the slow passage of the nutritive fluid produces a deposition of salts of 
lime. Similar secretions, from the same cause, are formed in the shells 
of animals. No deposition of solid substance could take place in shells 
or bones if the animal fluids circulated through them as quickly, inces¬ 
santly, and largely, as they do through the other parts of the body. But in 
plants where the circulation is much slower, small but nu¬ 
merous crystals are very frequently found. This subject Fig. 90. 
has been recently investigated by Prof. Bailey, who dis¬ 
covered that every species of oak, birch, chesnut, poplar, 
elm, locust, and all the common fruit trees, were filled, 
with crystals, crowded together in vast numbers. The 
size of these crystals was very small, being seen only 
by a powerful microscope, and measuring in some cases 
not more than the y- 1 -- of an inch in length; but their 
number was so great, that within the compass of a 
square inch of bark, not thicker than a sheet of writing 
paper, more than a million were collected together. 

Sometimes the arrangement of these crystals appeared 
like an elegant piece of mosaic work, as represented in 
Fig. 90, which is a section of the bark of a species of 
poplar. The existence of these crystals was first discovered by examin¬ 
ing the ashes of the oak, and they were afterwards found in the ashes of 
many other trees. The delicate crystal¬ 
line structure found in the ashes of the Fig. 91. 

maple leaf, is represented in Fig. 91. 

Most of the forest trees, not only in our 
own country, but in all parts of the 
world, are full of these crystals; so that 
they may be obtained for examination 
by merely scraping the wood into a 
watch-glass filled with water, and pick¬ 
ing out the woody particles, or by pre¬ 
paring the ashes of the wood with Can¬ 
ada balsam on a slip of glass. 

panic bodies generally developed? Are crystalline bodies found within 
plants ? Explain Figs. 90 and 91. What is said of the occurrence of isomeric 


_ 

— a 




© 

p 

3 

pg 



r~~\ 






















232 


ELEMENTS OF CHEMISTRY. 


5. Isomeric bodies , or bodies differing in properties but 
identical in composition, are of constant occurrence in organic 
chemistry. 

6. In the study of inorganic bodies, both analysis and syn¬ 
thesis are employed ; but in organic chemistry, analysis alone 
can be usually employed. Could we obtain the power of 
uniting life to matter, we might then build up its compounds 
and imitate its results. But as power to add life to dead mat¬ 
ter is and must ever be beyond our reach, we can destroy but 
cannot reproduce any of the forms of living matter. By 
breaking down the fabric we can learn the materials of which 
it is composed, but we cannot rear again the edifice. 

These are some of the effects of the agency of life on matter, 
which it is the object of organic chemistry to examine. As 
life is divided into animal and vegetable, so this subject in¬ 
cludes animal and vegetable chemistry. 

Animal chemistry will be reserved for the close ; vegetable 
chemistiy will at present occupy our attention, and will be 
considered under two sections, the non-azotized substances , or 
those substances which contain no nitrogen, and the azotized , 
or those bodies of which nitrogen is an element. 


VEGETABLE CHEMISTRY. 

318. Origin of plants. The seed retains the vital force in¬ 
active, but not lost. Air, heat, and moisture, call it forth in 
the process of germination. The presence of air is essential, 
for seeds will not germinate in the vacuum of an air-pump, 
nor when buried too deeply in the earth, where there is not a 
sufficient supply of air. It is not, however, the whole atmos¬ 
phere, but merely the oxygen of the air, which is necessary to 
the germination of seeds. These will germinate in pure oxy¬ 
gen,* but will not in nitrogen or hydrogen, unless these gases 

* But they will not continue to grow because the oxygen stimulates the vital 
processes to too great activity. Plants, as well as animals, die by the excess¬ 
ive stimulus of pure oxygen. Another substance must be mixed with it, and 
nitrogen is best adapted for this purpose. 


bodies in organic chemistry ? What method of investigation may be employed 
in organic chemistry ? How is organic chemistry divided ? How is vegeta¬ 
ble chemistry divided ? 

318. What must be present in the germination of seeds ? What constituent 





ORGANIC CHEMISTRY. 


233 


contain a mixture of oxygen. Chlorine dissolved in water 
appears to hasten the germination of seeds, but this is proba¬ 
bly owing to the gradual decomposition of the water by the 
chlorine, which takes the hydrogen, forming hydrochloric acid, 
and sets free the oxygen. All substances which readily yield 
a part of their oxygen to water accelerate the germination of 
seeds, but at the same time endanger the life of the young 
plant by exhausing the germ. 

When a seed is exposed in a moist and warm situation, it 
gradually imbibes moisture, and soon after emits carbonic acid, 
tormed by the union of a portion of its carbon with the oxygen 
of the water which it contains. But the process soon stops 
unless fresh oxygen is supplied from the atmosphere. None 
of this oxygen is absorbed by the plant, for all which has dis¬ 
appeared will be found by the carbonic acid given off. 

As the carbon is removed from the seed in the form of car¬ 
bonic acid, a rise of temperature will be' observed, which is 
very great when large quantities of grain are in a state of 
gemination. This is owing to the formation of carbonic acid, 
during which the carbon and the oxygen are condensed into a 
volume hardly greater than that which the oxygen occupied 
previous to their combination (100 cubic inches of carbonic 
acid contain 98 of oxygen) (93). The separation of carbon 
from the seed is also attended with the production of sugar, 
which is formed from the union of the oxygen and the hydro¬ 
gen with the carbon which remains (320). 

319. The process of germination is very different in different 
plants. If we expose some beans to the action of heat, air 
and moisture, a small radicle soon appears shooting down¬ 
wards to form a root, and at the same time, or soon after, the 
plumula or stem extends upwards. The growth, thus far, 
takes place from the germ within the seed, and is supported 
by elements derived from the seed itself. But when the 
plumula appears above the ground, and expands its earliest 
leaves, the plant commences a new existence. The radicle 
sinks down into the earth, and extracts sap, which, in the new- 
— formed leaves, is converted into nourishment for the growth 
of the plant. 

Before the plumula and its first leaves are fully developed, 
a very important office is performed by the cotyledons of the 
seed. Beans have two cotyledons, or two divisions, a and b 

of tlie atmosphere is essential to germination ? To what extent does germin¬ 
ation take place, when a seed is exposed in a moist and warm situation which 
is deprived of oxygen 1 To what is the rise of temperature which is observed 
in the germination of seeds owing 1 How is sugar foi’med 1 

319. Explain the method in which beans germinate. Describe Pig. 92 







234 


ELEMENTS OF CHEMISTRY. 


(Fig. 92), into which the seed is separated, as the germ within, 
c, increases in size. These remain in connection with the 
germ, and vessels make their 
appearance (Fig. 93), which 
send down branches into the 
radicle for its nourishment, and 
through the radicle (for there 
is no direct communication be¬ 
tween the cotyledons and the 
plumula) to supply nourish¬ 
ment to the plumula. The 
cotyledons are seminal leaves which remain till the plumula 
and its new-formed leaves have so far increased in size, that 
these can prepare for the use of the plant the food (the sap) 
introduced by the radicle. When this is accomplished, the 
cotyledons decay and drop off, and the plant carries on by 
itself all the processes of vegetation. 

Seeds which do not form two cotyledons, produce, with few 
exceptions,* but one cotyledon ; this is generally hid within 
the integuments of the seed, seldom rising above the ground, 
and never assuming the appearance of a green leaf. 

j Leaves, the ornament of the vegetable creation, are designed 
to perform a most important office in plants. They corre¬ 
spond at once to the stomach and the lungs of animals ;—to 
the stomach in digesting and preparing the food which 
reaches them through the sap vesselsto the lungs in ex¬ 
haling and inhaling gases, This takes place through mouths 
or stomata , generally on the under surface of the leaf, although 
watery vapor is chiefly transpired through the upper surface. 
By transpiring moisture the leaves concentrate the sap which 
passes through them. This not only loses the greater part of its 
water, but also undergoes other changes. If in the direct sun¬ 
light, the carbonic acid of the sap is decomposed, its oxy¬ 
gen exhaled through the stomata on the under surface of the 
leaves. If in the shade or at night, carbonic acid is given 
off into the atmosphere. Other changes take place in the sap, 
for this returns from the leaves modified to suit the wants of 
the particular plant, or converted into the peculiar juice of 
the plant. Hence it is that grafting causes different branches, 

* The cupressus pendula has three cotyledons; the pinus inops and the 
ceratophyllnm demersum, four; the pinus laricio, five; the taxodium disti- 
*chum , six; the pinus strobus, eight; and the pinus pinea, ten or twelve. 




Fig. 93. What are cotyledons ? How many cotyledons has the bean ? What 
is said of seeds which form but one cotyledon ? What purposes do the 
leaves of plants serve ? 






ORGANIC CHEMISTRY. 


235 


leaves, and fruits to be produced on the same stock. In the 
leaf is the seat of nearly or quite all the modifications which 
the sap undergoes, and by which it is prepared to form the 
wood, new leaves, the flower and the fruit. It not only gives 
off watery vapor from its upper surface, but in wet weather 
absorbs it and rain through the under surface, so as often to 
increase very much in weight during a period of rain. 


§ 


SECTION I.—NON-AZOTIZED BODIES. 


SECT. I.-1. THE STARCH GROUP. 


320. Three of the four elements of the organic kingdom 
are contained in this group ; carbon, hydrogen, and oxygen, 
of which hydrogen and oxygen are always in equal proportions, 
or in the proportions to form water. 

Starch (dextrine), C 12 ® 10 0 1 0 • 

Cane sugar, (crystallized), C 12 H 11 0 11 . 



Grape sugar, 
Milk sugar, 
Gum, 
Cellulose, 


Starch , or fecula, is a body of great interest in many re¬ 
spects, from its universal occurrence in the vegetable kingdom, 
the important offices it there fulfils, and the various changes 
it may be made to undergo. There is scarcely a plant or a 
part of a plant which does not yield more or less of this sub¬ 
stance. Frequently the quantity is so great that it produces 
in the plant an enormous distention of the cellular tissue. 
Thus the potato is swollen out of all shape or regular figure 
by an accumulation of starch mingled with water within the 
cells. Starch constitutes a very important and often a very 
abundant ingredient in seeds of all kinds. The interior of the 
stems of many palms is often filled with loose cellular sub¬ 
stance rich in starch. 

If a fresh plant is bruised and macerated m water, and 
the liquid then squeezed out through a linen cloth, a large por¬ 
tion of the starch will pass with the juice from the vegetable 
tissue, and will settle after standing as a mealy mass, p ota¬ 
toes, grain, and many orchidaceous plants, are very rich in 







236 


ELEMENTS OF CHEMISTRY. 


Fig. 94. 



starch. Starch is a white, pulverulent, opaque powder, whi< 
under a powerful microscope is found to consist of small, ge 
erally regular, grains or globules. Their appearance with 
the cells of the plant is shown in Fig. 9 
which represents a section of some of t] 
cells of the potato. The starch granul 
from different plants vary both in magi 
tude and form. Several of these forms a 
exhibited in the accompanying figure 
Fig. 95 represents potato starch. The 
granules glisten in the sun; they are ha: 
to the touch, and are always of a pulvef 
lent rather than a concrete character. Th 
are egg-shaped grains, with scales ovt 
lapping each other, and on one side each granule exhibits 
dark lines, as at a. The granules of wheat (Fig 96) are mw 
smaller than those of potato starch: They a 
also much harder. The granules of pd 
(Fig. 97) are also much smaller than those 
the potato. Arrowroot is a starchy meal, pi 
pared in the East and West Indies, from t 
roots of some marsh plants. Its granules a 
intermediate in size between those of whe ! 
and those of the potato. They are transp 
rent when examined by the microscope, ar 
therefore, they form a powder of less brilliant whiteness th 
that of wheat. 

Sago is prepared by gently heating star 
Fig. 96. with constant agitation, till it dries up into ha: 

horny, granules. The genuine sago comes frc 
India, where the starch for its preparation is < 


Fig. 95. 



q f jf tracted from the pith of many of the palm tre > 
Cp f) ^ Tapioca is prepared from the root of a Son 1 


American plant, which is now 
also cultivated for this purpose 
in the West Indies. This root contains a 
poisonous juice from which it is purified by 
pressure and heat. 

When starch is put into cold water, and 
the water gently heated, its properties are < 
completely altered. At a temperature a lit- 


Fig. 97. 




t? o' 1 

O o 


Write the bodies of this group and their constitution. What is said of start ! 
Explain Figs. 94, 95, 96, and 97. W^hat is the action of hot water on start i 
Mention some of the properties of starchthe principal test. 





ORGANIC CHEMISTRY. 


237 


> below the boiling point the granules burst, and their con- 
nts form with the water a nearly transparent, gelatinous 
ass. This is freely miscible with water, if not in fact dis- 
lved in that liquid. Minute shreds of membraneous matter 
e discovered floating in the liquid, which are the envelops 
each granule of starch. These give to the solution a slightly 
•alescent appearance. The swelling of many of our most 
mmon articles of food, such as rice, barley, beans, peas, &c., 
hen boiled with water, is owing to the large amount of starch 
hich they contain. 

Starch is insoluble in cold water and in alcohol, and is pre- 
pitated by many of the metallic oxides, as lime, baryta, and 
:ide of lead, and also by a large addition of alcohol. By far 
;e most characteristic reaction, however, is that with free 
dine, which forms with starch a deep indigo-blue compound 
Mine of starch), which dissolves in pure water, although it 
insoluble in free acid or saline matter. The blue liquid loses 
5 color by heat, and this loss is permanent if the boiling is 
ng continued. In this case the iodine is volatilized, and the 
ue compound therefore decomposed. If, however, the heat 
* quickly withdrawn, before the temperature reaches 212°, 
e color returns, as the iodine is, in this case, not entirely 
ilatilized. When put in a dry state into iodine, starch 
squires a purplish black color. 

321. Dextrine and grape sugar. Thick gelatinous starch, 
hen boiled for a few minutes with dilute acid, changes to a 
rid as limpid as water. If the acid is neutralized with car- 
mate of lime, and the liquid gently evaporated to dryness, a 
ibstance is obtained having the appearance and many of the 
laracters of gum. This substance is called dextrine , or 
raimy starch. In chemical composition it is precisely the 
•me as starch. If, instead of interrupting the ebullition as 
un as the mixture of acid and starch has become clear, we 
•ntinue it for several hours, adding from tirrife to time small 
rantities of water to supply the place of that lost by evapora- 
on, and then separate the acid, and boil down the solution to 
small bulk, we obtain a sirupy liquid, very sweet to the 
iste, which, on standing for a few days, entirely solidifies to 
mass of grape sugar. This product exceeds in weight the 
arch from which it was obtained. 

In the transformation of starch to dextrine, no change of 
imposition is produced, and none also in the change of dex- 


21. How may dextrine be formed ? What is the composition of dextrine ? 
y may grape sugar be formed ? What is diastase ? What is its action. 



238 


ELEMENTS OF CHEMISTRY. 


trine to grape sugar, except the absorption of the elements of 
water. The acid employed is withdrawn at the end of tin 
experiment in its original amount, and nothing is absorbed fron 
the air. Starch is also converted into sugar, by the action of 
a peculiar ferment, called diastase , which is contained in an 
infusion of malt. Diastase is also found in germinating seeds 
and buds while developing. It dissolves and converts to food 
the starch which is stored up for the nourishment of the young 
plant. By diastase, gelatinous starch may be converted in -a 
few minutes, at a temperature of 160°, into dextrine, and soon 
after into grape sugar. 

In germination, potatoes become soft, mucilaginous, and 
afterwards sweet; the dextrine formed from the starch renders 
them mucilaginous, and the sugar formed from the dextrine 
renders them sweet. The quantity of starch in potatoes is 
found to vary in different months. In August 100 pounds of 
potatoes contained 10 pounds of starch ; in September, 14 
pounds; in October, 15; in November, 16; in December, 17 ; 
in January, 17 ; in February, 16 ; in March, 15 ; in April, 13 ; 
in May, 10. The starch, therefore, increases during the win¬ 
ter, and in the spring, after the germinating principle is ex¬ 
cited, it diminishes. Unripe apples and pears contain starch, 
as is shown by the test with iodine. When completely ripe 
they cease to give this reaction, the starch having become con¬ 
verted into dextrine and sugar, which gives a sweet taste to 
the fruit. Frost produces a similar effect on those vegetables 
which are rich in starch ; hence frozen potatoes, apples, &c„ 
have a sweet taste after being thawed. 

Grape sugar is abundantly diffused throughout the vegeta¬ 
ble kingdom. It may be extracted in large quantity from the 
juice of sweet grapes, and also from honey, of which it forms 
the solid crystalline portion, by washing with cold alcohol, 
which dissolves the fluid sirup. It is found in many vegetables, 
and is especially abundant in fruits, as plums, pears, figs, 
grapes, &c. The white coating of plums, and the white, sweet 
grains in raisins, consist of it. Compared with cane sugar it 
is much less soluble in water. One ounce of cold water will 
dissolve three ounces of cane sugar, but only two-thirds of an 
ounce of grape sugar. It is also much less sweet. Two and 
a half, ounces of grape sugar are equivalent to only one ounce 
of common sugar in this respect. The crystals of cane sugar 


upon starch ? Why do potatoes in germination become mucilaginous and after¬ 
wards sweet 1 What is said of the quantity of starch contained in potatoes in 
the different months of the year 1 When do apples and pears contain starch ? 
What becomes of this starch when the fruit ripens ? What is said of grape 



ORGANIC CHEMISTRY. 


239 


are bold and distinct; grape sugar separates from its solutions 
in granular warty masses presenting crystalline faces but 
rarely. When pure it is nearly white. Alkalies, which turn 
grape sugar brown, produce little effect on cane sugar, and 
sulphuric acid dissolves grape sugar without blackening, but 
turns common sugar black. By these two tests, therefore, 
grape and cane sugar may be distinguished. Another test is 
to add caustic potash to the sugar mixed with a solution of 
copper. When this mixture is heated, grape sugar throws 
down a green precipitate, which turns deep red, while the so¬ 
lution is left colorless. The action with cane sugar is very 
different. The mixture in this case alters very slowly, gradu¬ 
ally forming a red precipitate, and leaving the solution blue. 

Cane sugar is found abundantly in the juices of many plants, 
but is chiefly extracted from the sugar cane. By evaporating 
the' cane liquor, it is crystallized in large rhombic prisms, 
which are colorless. Sugar is permanent in the air, phospho¬ 
rescent by friction and electricity, and of the sp. gr. 1*6. It 
has a pure sweet taste, and is very soluble in water, uniting 
with a third of its weight of cold water, and dissolving to an 
almost unlimited extent in hot water. It is dissolved by alco¬ 
hol, but not as readily, and in absolute alcohol it is almost in¬ 
soluble. When heated, it melts and gives rise to a yellowish 
transparent body, called barley sugar. If kept at a tempera¬ 
ture of 630° it turns to a reddish-brown substance called 
caramel. Sugar has the property of combining like an acid 
with some bases, as potash, lime, ammonia, oxide of lead, &c. 
These compounds are called saccharates. 

Sugar is a powerful antiseptic, and is now used to a consid¬ 
erable extent for preserving meat and fish, for which purpose 
it possesses the advantage of acting in a much less quantity 
than is requisite of common salt, and of not destroying the taste 
nor impairing the nutritive qualities of the food. 

In many parts of the continent of Europe, sugar is manu¬ 
factured on a large scale from the beet root , which contains 
about 8 per cent, of that substance. Large quantities are also 
obtained from the sap of the maple-tree. 

Milk sugar , lactine, is obtained in large quantities by evap¬ 
orating whey to a sirupy state, and purifying by animal char- 


sugar. In what respects does it differ from cane sugar? By what tests may 
these two kinds of sugar be distinguished? In what plants is cane sugar 
found ? Mention some of its properties. How is it converted into barley 
sugar—caramel ? What is said of the action of sugar with the bases ? What 
are its compounds called ? Wliat is said of the antiseptic properties of sugar ? 
How is milk sugar obtained ? Mention some of its properties. What body is 




240 


ELEMENTS OF CHEMISTRY. 


coal the lactine which slowly crystallizes out. It is much 
less sweet than either cane or grape sugar. It is also harder 
and less soluble, requiring 5 or 6 times its weight of cold, 
and times its weight of hot water to dissolve it. When 
mixed with hydrochloric or sulphuric acids, it becomes con¬ 
verted into grape sugar, and this change is hastened by boil¬ 
ing. It forms four-sided prisms which are white, translucent, 
and of great hardness. When heated it loses water, and at a 
high temperature blackens and decomposes. A peculiar acid, 
called lactic acid , is formed from milk sugar when allowed to 
stand, and this acid coagulates the milk, and causes it to turn 
sour (415). 

322. The sweet principles of plants appear to be rather 
numerous. Already five or six distinct bodies of this kind 
have been pointed out and examined, and it is probable that 
others exist which are yet undescribed. Thus, besides the 
sugar of cane, beet root, &c., a second variety constitutes the 
sweet matter of all ordinary fruits ; a third is found in certain 
fungi ; a fourth in common liquorice ; a fifth exists in manna, 
which is an exudation from a species of ash in southern Europe; 
a sixth is found in milk. 

323. Gum—Gum Arabic. Gums of various kinds exist in 
many plants, and often in such abundance that they exude from 
the bark as a viscid liquid, and harden upon it in transparent 
globular masses. Examples of this kind are found in beech 
and cherry trees. Gum Arabic comes from an African tree, a 
species of acacia, from which it exudes spontaneously. It is 
the best type of this class of bodies. It forms white or slightly 
yellowish irregular masses, which are destitute of crystalline 
structure, and break with a smooth conchoidal fracture. It is 
bleached by exposure to the sun, and its powder is nearly or 
quite white. It is soluble in water, forming a viscid, adhesive, 
tasteless solution, from which pure arabine , or the soluble gum¬ 
my principle, may be precipitated by alcohol. It undergoes 
no change by time when kept in a dry place. Its aqueous solu¬ 
tion, if strong, remains for a considerable time unaltered, but 
at length becomes sour, in consequence of the production of 
acetic acid (333). At a temperature between 300° and 
400°, it becomes soft, and may be drawn into threads. Gum 


formed when milk is allowed to stand? What effects does lactic acid produce 
on milk ? 

322. How many sweet principles have been discovered in plants ? Mention 
some of these. 

323. Whence is gum Arabic obtained ? Mention some of its properties;— 
its uses;—its composition. 



ORGANIC CHEMISTRY. 


241 


or arabine (C 12 H 1 jO, l .) is isomeric with crystallized cane 
sugar. 

324. Pectine and pectic acid have the same composition 
CijHjO,,. Pectine exists more or less in all vegetables, es¬ 
pecially in those fruits and roots from which jellies are pre¬ 
pared. To the juices of these fruits, especially when boiled 
with sugar, it gives the property of hardening into a gelatinous 
mass on cooling. From vegetable juices it may be precipitated 
by alcohol. As thus obtained, it forms when moist a transpa¬ 
rent jelly, imperfectly soluble in water, and tasteless, which 
dries up to a translucent mass. It is very nearly allied to the 
gums. 

By the agency of a fixed alkali or alkaline earthly base, 
pectine is instantly converted into pectic acid , which unites 
with the base to form a pedate. On the addition of an acid 
to this pectate, it is decomposed and the pectic acid liberated. 
This acid is in the form of a colorless jelly, slightly acid, 
scarcely soluble in cold water, more soluble in hot water. 

325. Cellulose, vegetable tissue, lignine , is that portion of 
every plant which remains behind after the action of several 
solvents, such as water, dilute acid and alkali, alcohol and 
ether, have been successively applied. By these solvents the 
gum, sugar, resin, coloring-matter, &c., are removed, and there 
is left behind a white fibrous skeleton which 

is cellulose. This is the fundamental ma- 98 - 

terial of the structure of plants. It is em¬ 
ployed in the organization of eells and ves¬ 
sels of all kinds. What bone, flesh, and 
skin, are to the animal, cellulose is to the 
plant. 

In Fig. 98, is represented a transverse 
section of the sugar eane as seen by the 
microscope. This is so thin as to display only one layer of 
cells, but a thicker section would show a second set of the 
same kind of cells behind the first. The forms of vegetable 
cells are exceedingly various, being globular in some plants, 
angular in others, and of the latter some are three-sided, 
others square, but the greater part are hexagonal or six-sided 
figures, (p. 233.) 



324. What is said of pectine ? How is pectine converted into pectic acid ? 
What are some of the properties of this acid ? 

325. What is cellulose? What are some of the different forms under 
which it occurs? Where is cellulose seen in a state of purity? Mention 
some of its properties. How may the cellulose of linen aud cotton be distin¬ 
guished ? 

11 




242 


ELEMENTS OF CHEMISTRY. 


In the young leaves, and in the pulp of fruit and roots, as 
apples, plums, carrots, &c., cellulose is very finely ramified, 
tender, soft, and easily digestible ; in straw, wood, and the 
husk of grain, it is hard and indigestible ; it forms the stones 
of plums, cherries, and peaches, and the shells of nuts, and also 
the light pith of the elder, the substance of cork, and the long 
pliant fibres of hemp, flax, and cotton. Under a good micro¬ 
scope the ultimate fibres of cellulose present the appearance of 
minute ribands with rolled or thickened edges. 

Cellulose is seen in a state of purity in the fibres of linen 
and cotton. It is of perfect whiteness, insoluble in water and 
alcohol, and tasteless. Strong and cold sulphuric acid con¬ 
verts it into dextrine. When digested in fused potash, dis¬ 
solved in its weight of water, linen yam becomes immediately 
yellow, while cotton remains white, and in this way these two 
forms of cellulose may be distinguished. They may also be 
distinguished by the appearance of their fibres under the mi¬ 
croscope. The fibres of cotton are flat, riband-like, and more 
or less contorted or shrivelled ; those of linen are straight, 
round, and with cross knots at certain distances. 

326. Wood consists chiefly of cellulose. Dry timber con¬ 
sists on an average of 96 parts of fibrous and 4 of soluble 
matter in 100, but these proportions vary somewhat with the 
season, Jfie soil, and the plant. Wood becomes snow-white 
when exposed to the action of chlorine. If too long exposed, 
th§ chlorine destroys the vegetable tissue by abstracting the 
hydrogen. When dipped in strong sulphuric acid, wood is 
blackened because the acid attracts from it hydrogen and oxy¬ 
gen and leaves carbon in excess. The oxygen and hydrogen 
unite to form water by the presence of sulphuric acid (dispos¬ 
ing affinity, p. 64), and the water thus formed unites with the 
sulphuric acid. When digested with dilute sulphuric acid, it 
is transformed first into dextrine, and afterwards, by ebullition 
with water, into grape sugar. By nitric acid wood is dyed 
yellow, being oxidized by this acid. By long continued treat¬ 
ment, all the carbon may be oxidized into carbonic acid, and 
all the hydrogen into water. 

Wood is more dense than water, and floats only by the air 
which it contains in its pores. The specific gravity of white 
wood, of maple, or of fir, is about 1.46 ; that of oak about 1.53, 
although the density of all kinds of wood varies greatly with 


326. Of what is wood chiefly composed ? What is the action of chlorine 
upon wood ?—strong sulphurie acid ? Into what is wood converted when di¬ 
gested with dilute sulphuric acid ? What is the action of nitric acid on wood ? 
Why does wood float on water ? 



ORGANIC CHEMISTRY. 


243 


the age of the tree, and with the climate and soil. Those 
trees which grow on a poor soil, in high situations exposed to 
the wind, have their woody fibres more dense and closely 
packed together, than if grown in a protected spot, or upon a 
moist, rich soil. G-reen wood contains, on an average, 40 per 
cent, of water (from 20 to 50 per cent.) When dried or sea¬ 
soned in the air for a year, it still retains from 20 to 25 per 
cent, of water. If dried at a strong heat, or kiln-dried, it yet 
retains 10 per cent, of water, and begins to char before parting 
with it all. Thoroughly kiln-dried wood afterwards absorbs 
from the air 10 or 12 per cent, of water. 

327. Gun-cotton, pyroxiline, is explosive vegetable tissue, 
prepared by oxidizing cotton with nitric acid. Half an ounce 
of the strongest -nitric acid (sp. gr. 1.5) is mixed with an ounce 
of strong sulphuric acid. The object of the latter is to attract 
and retain the water contained in the nitric acid, and that 
which separates from the cotton. This mixture is poured into 
a porcelain mortar or bowl, and as much cotton pressed in 
with the pestle as can be moistened with the acid. Loose 
cotton is not essential, as cotton cloth, wick yarn, printing 
paper, &c., will answer. When the cotton has soaked for five 
minutes, it is taken out with a glass rod, put into a vessel of 
water, and washed repeatedly with fresh portions of water 
Hindi it no longer reddens blue test-paper. The cotton is then 
squeezed out with the hand, spread upon a sheet of pa*per, and 
dried in an airy place. It is dangerous to dry it on a stove, as 
it easily takes fire. One hundred parts of pure lignine yield 
176 of pyroxiline. It is white, inodorous, insoluble in water, 
soluble in ether and caustic potash. When touched with a 
red-hot iron it explodes, and leaves no residue. By a stroke 
of a hammer the part struck explodes and drives off the re¬ 
mainder unconsumed. Its power in propelling balls is about 
eight times greater than that of gunpowder. This great 
energy depends upon the fact that it is completely resolved by 
its combustion into aqueous vapor and permanent gases, which 
are carbonic acid, carbonic oxide, and nitrogen. Its purity 
(i. e. the conversion of the lignine of which it is made into 
pyroxiline) may be ascertained by sulphuric acid of the density 
1.4 to 1.76, which dissolves it if pure without becoming colored, 
but if lignine is present the acid is soon colored. 

Collodion is a solution of an impure form of gun-cotton in 
ether. In its preparation the process for the manufacture of 


327. What is gun-cotton 1 How is it prepared ? _ Mention some of its prop¬ 
erties. To what is the great energy of its explosion owing ? How may its 
purity be determined ? What is collodion 1 




244 


ELEMENTS OF CHEMISTRY. 


gun-cotton is so modified that the product is less inflammable 
than this substance, and leaves after explosion a black or car¬ 
bonaceous residue. Two parts of nitrate of potash are dis¬ 
solved in three parts of concentrated sulphuric acid, or in a 
larger quantity of the commercial acid. Into this solution the 
cotton is plunged and left for one or two hours. It is after¬ 
wards taken out and washed in a large quantity of water, and 
dried as in the process for gun-cotton. The cotton thus pre¬ 
pared is put with the ether in a well-stopped bottle, in the 
proportions of 8 cotton to 125 rectified ether. After the bottle 
has been well shaken, 8 parts of rectified alcohol are added by 
degrees. The whole is shaken till the liquid acquires a sirupy 
consistence. It may be then passed through a cloth (filtering 
through paper or any other fine filter would impair its quality 
by removing the fine fibres, which, by felting with each other, 
give a greater degree of tenacity and resistance to the dried 
mass). The liquid is received into well-stopped bottles. 

So adhesive is collodion prepared in this way, that when a 
piece of cotton or linen cloth is wet with it, and applied to the 
hand, and the liquid allowed to evaporate, the cloth may be 
made to support 20 or 30 pounds, and will generally be torn 
before it gives way. The part to which collodion is applied 
should be completely dry, as water prevents its adhesion. 


SECT. I. -2. ORGANIC ACIDS. 

328. Sulphuric, nitric, and other inorganic or mineral acids 
are formed artificially, but the acids which are now to bo de¬ 
scribed are the product of the vital principle alone. By de¬ 
composing these acids we arrive at their constitution, but we 
cannot again unite their elements to form these bodies. The 
following table includes the most important of these acids : 

Oxalic acid, C 2 0 3 , HO + 2HO. 

Tartaric acid, C 8 H 4 O 10 , 2HO. 

Acetic acid, C 4 H 3 0 3 , HO. 

Citric acid, ' C^HgOj,, 3HO. 

Malic acid, C 8 H 4 0 8 , 2HO. 

Tannic acid, C 18 H 5 0 9 , 3HO. 

Gallic acid, C 7 H0 3 , 2HO. 

329. Oocalic acid is formed by the action of nitric acid on 
starch, sugar, and many other substances. It is the highest 


328. How are the organic acids produced 1 

329. How is oxalic acid formed ? What is said of the amount of oxygen 
which it contains ? Mention some of the properties of oxalic acid 1 Write and 




ORGANIC CHEMISTRY. 


245 


state of vegetable oxidation, for if more oxygen be added it 
loses its vegetable nature, and is resolved into carbonic acid 
and water. In its formation, this excess of oxygen which it 
contains compared with any other organic compound, is fur¬ 
nished by nitric acid. It may also be obtained from organic 
substances by the action of caustic potash. Thus if wood-shav¬ 
ings be mixed with a solution of caustic potash, and exposed 
to a heat considerably higher than 212°, they will be partially 
decomposed, and converted into oxalic acid, which then com¬ 
bines with the alkali forming oxalate of potash. This is per¬ 
haps the cheapest method of obtaining oxalic acid. 

Oxalic acid is a colorless crystallized solid, possessing con¬ 
siderable volatility, and a strong sour taste. Its crystals have 
the shape of slender, flattened, four or six-sided prisms. They 
dissolve in about nine times their weight of cold, and in their 
own weight of boiling water. They are also soluble in alcohol. 
Oxalic acid is very poisonous. Instances are on record of its 
proving fatal in ten minutes, and few survive the effects of a 
poisonous dose beyond an hour. Magnesia and chalk are the 
proper antidotes. 

According to the formula C 2 0 3 , HO + 2HO, crystals of oxalic 
acid contain 1 eq. of basic water (water of constitution), with 
two eq. of water of crystallization. • The latter may be removed 
by exposure to a low heat, and the acid then becomes a white 
powder and sublimes without difficulty. The symbol of the 
acid in this state will be C 2 0 3 , HO (omitting 2HO from the 
above formula). Any attempt to simplify its constitution still 
farther by driving off the basic water HO, in order to isolate 
the acid as C 2 0 3 , is attended by its decomposition, as follows*: 

C 2 0 3 + HO=oxalic acid with basic water. 

This may be divided into 

HO—water. 

[escapes in watery vapor.] 

C0 2 = Carbonic acid. 

[first product of the decomposition of oxalic acid.] 

CO= Carbonic oxide. 

[second product of the decomposition of oxalic acid.] 

Oxalic acid occurs naturally in several plants, in union with 

■* The water, however, can be entirely separated by combining oxalic acid 
with certain bases, as the oxides of silver and lead, which form oxalates, leav¬ 
ing the composition AgO,*C 2 0 3 , and PbO, C 2 0 3 , water having been ex¬ 
cluded. 


explain its formula. What portion of the water contained in crystals of oxalic 
acid may be expelled by heat ? What will the formula then become ? Ex¬ 
plain the diagram. What is said of the relations of oxalic to the other acids? 
How does oxalic acid occur naturally ? What is the best test for oxalic acid ? 
Mention some of the uses of this acid ? 




246 


ELEMENTS OF CHEMISTRY. 


potash or lime. It has a very strong affinity for lime, and 
forms with it an insoluble precipitate of oxalate of lime, when¬ 
ever the acid and the earth are brought into contact. Hence 
oxalic acid, and its soluble combinations, are the best tests for 
lime which we possess ; and lime, on the other hand, is the 
best test for oxalic acid. So strong is the mutual attraction 
between this acid and lime, that the former takes the latter 
even from sulphuric acid. Hence the addition of a soluble 
oxalate produces a white cloud in a solution of sulphate of 
lime. Oxalic acid is used in calico printing, and in removing 
ink spots from linen or paper. This it does by dissolving the 
oxide (sesquioxide) of iron, and both are removed by washing. 
Its use in both cases depends upon its property of forming a 
soluble and nearly colorless compound with the sesquioxide of 
iron, which is the basis of ink, and also the yellow color in 
calico when oxalic acid is used to produce white patterns. 

330. Tartaric acid is the acid of grapes, of tamarinds, of 
the pine-apple, and several other fruits, in which it occurs as 
bitartrate of potash. Tartrate of lime is also occasionally met 
with. Tartaric acid is a white crystallized solid, in the form 
of irregular six-sided prisms. It is unalterable in the air, and 
possesses a strong acid taste which becomes agreeable when 
the acid is sufficiently diluted with water. It is soluble in five 
or six times its weight of cold, and twice its weight of boiling 
water. It is also soluble in alcohol. The solution reddens 
litmus strongly. Its weak aqueous solution, like those of most 
of the organic acids, is decomposed by keeping, becoming covered 
with a mouldy pellicle. 

331. Acid tartrate of potash, cream of tartar KO, HO, 
C 8 H 4 0j 0 . During the fermentation of grape juice a crystal¬ 
line, stony matter is deposited. This consists chiefly of acid 
tartrate of potash, with a little tartrate of lime and coloring 
matter, and is the source of all the tartaric acid of commerce. 
It is purified by solution in hot water, and the coloring matter 
is removed by animal charcoal. It forms small, transparent or 
translucent, prismatic crystals, irregularly grouped together, 
which are hard and gritty between the teeth, and dissolve 
slowly .in the mouth. It is permanent in the air, and soluble 
in 15 parts of boiling water, but the greater part separates on 
cooling, leaving about T | T or less dissolved in the cold liquid. 
Its solubility in water is greatly increased by the addition of 


330. Write and explain the formula for tartaric acid. Where is this acid 
found ? Mention some of its properties. 

331. Write and explain the formula for cream of tartar 1 How is this sub¬ 
stance produced ? Mention some of its properties. 



ORGANIC CHEMISTRY. 


247 


borax. It is insoluble in alcohol. It has an acid reaction and 
a sour taste. 

332. Tartrate of antimony and potash , tartar emetic , KO, 
Sb 2 0 3 , CgH^Oj 0 + 2 HO, is made by boiling oxide of antimony 
in solution of cream of tartar. It is deposited from a hot and 
concentrated solution in crystals derived from an octahedron 
with a rhombic base, which dissolve in 15 parts of cold and 3 
of boiling water. The solution is decomposed by both acids 
and alkalies. Sulphuretted hydrogen separates all the anti¬ 
mony as a sulphuret. Crystals of tartar emetic are colorless, 
and have an acid and extremely disagreeable taste. When 
exposed to the air they effloresce and become opaque. 

333. Acetic acid , piyroligneous acid , vinegar. When alco¬ 
hol is oxidized it is converted into vinegar. This does not take 
place by mere exposure to the air, or even to oxygen gas, as 
pure alcohol is not affected by either of these. To produce this 
effect it is necessary to add a ferment , as yeast, vinegar, &c., 
which, by disposing affinity (p. 69), generates an action that 
would not exist without its presence. A tub, a , (Fig. 99.) 12 
or 15 feet high, is filled with shavings of beech-wood, and is 
furnished with a perforated 

shelf, b, near the top. Through Fi S- "* 

this shelf small holes are 
made, and strings let down 
with knots tied in the upper 
extremities, whieh prevent 
them from falling through. 

The alcohol is poured into the 
tub above the shelf b, and 
trickles down slowly over the 
threads, and thus diffuses it¬ 
self over the shavings, form¬ 
ing a very thin layer, which 
presents to the air a surface 
many thousand times more 
extensive than was produc¬ 
ed by any former method. 

Several large holes c, c , are 
bored around the lower part 
of the tub, and also in the perforated shelf at d, d , d, to pro¬ 
duce a free circulation of air. The large holes d , d , d, are 



332. Write and explain the formula for tartar emetic. How is tartar emetic 
made? Mention some of its properties. TT . . .. 

333 Write and explain the formula for acetic acid. How is acetic acid 
formed 1 Explain Fig. 99. Mention some of the properties of acetic acid. 



















































248 


ELEMENTS OF CHEMISTRY. 


filled with tubes which rise above the alcohol upon the per¬ 
forated shelf. The process of fermentation within the tub pro¬ 
duces an elevated temperature (104°). The heated air, there¬ 
fore, rises and passes off through the tubes d, d, d, while fresh 
air enters at c, c, and thus a circulation is kept up within the 
tub. The air passing through the shavings within, gives up 
its oxygen to the alcohol, and converts it into vinegar. The 
ferment used in this process is strong vinegar, with which the 
tub and the shavings are previously moistened. Brandy, beer, 
wine, &c., may be converted into vinegar in a few hours by 
being passed through the tub three or lour times 

Alcohol (0 4 H 6 0 2 ) first absorbs 2 from the atmosphere. This com¬ 
bines with 2H of the alcohol to form water (2HO), leaving C 4 H 4 0 2 . 
This is aldehyde. Aldehyde has a strong affinity for oxygen, of which it 
absorbs 2 atoms (2) from the atmosphere, and is thus changed into C 4 
H 4 0 4 or acetic acid. Aldehyde is a very volatile liquid, boiling at 70°; 
if, therefore, the air is not sufficiently renovated, so that the aldehyde 
can absorb oxygen as fast as it is formed, a large quantity of it will es¬ 
cape, and there will be a proportionate loss of acetic acid. Even when 
the process is properly conducted, about yj of the acetic acid is lost. 
Acetic acid is also distilled from wood (p. 260) in combination with a 
peculiar oil, which gives it a peculiar odor, and disguises its properties to 
such an extent that it was formerly supposed to be a distinct acid. It 
received the name of pyroligneous acid which it still retains. Acetic 
acid may also be prepared by various other processes. 

In the United States, vinegar is usually made from cider, 
which, by long exposure to the atmosphere, attracts additional 
portions of oxygen, and is converted into acetic acid. The 
yellow or brownish color is often imparted to it by burnt sugar, 
or extract of chicory. 

Dilute acetic acid, or distilled vinegar, used in medicine, 
should always be examined for lead or copper, as it sometimes 
contains these impurities, derived from the metallic vessel or 
condenser used in the process. The strength of any sample of 
acetic acid cannot be safely inferred from its density, but is 
easily determined by the quantity of dry carbonate of soda 
necessary to saturate a known weight of the liquid. The water 
contained in vinegar freezes on exposure to cold sooner than the 
acid ; hence, in this way, weak vinegar may be strengthened. 
The same action is observed when wine is exposed to the cold. 

Acetic acid unites in all proportions with water, and dis¬ 
solves to a certain extent in alcohol. It is a solvent of a great 
number of substances, such as the volatile oils, camphor, gluten, 
resins and gum-resins, fibrine, albumen, &c. It is one of the 
few vegetable acids that volatilize without decomposition. Its 
boiling point is somewhat higher than that of water, and when 
boiled in open vessels it takes fire, and burns with a blue flame 


ORGANIC CHEMISTRY. 


249 


like alcohol. It attracts humidity from the atmosphere, and 
should, therefore, be preserved in well-stopped bottles. Com¬ 
mon table vinegar contains from three to five per cent, of acetic 
acid, besides unfermented substances which were contained in 
the alcohol. If vinegar contains even a trace of sulphuric acid 
(with which it is often adulterated), it will dissolve starch 
readily when heated ; but, if pure, it will not act upon starch.' 

334. Acetate of lead, PbO, C^HgOg + 3HO, is prepared on 
a large scale by dissolving litharge in acetic acid. It may be 
obtained in colorless, transparent, brilliant needles, which are 
prisms with dihedral summits. It is usually obtained in com¬ 
merce as a confusedly crystalline mass, somewhat resembling 
loaf-sugar. From this fact and from its sweet taste it is called 
sugar of lead. The crystals are soluble in about T \ part of 
cold water, effloresce in dry air, and melt when gently heated. 
The water of crystallization is easily driven off by heat, and 
the salt in the anhydrous state obtained. Acetate of lead is 
soluble in alcohol. The watery solution has an intensely 
sweet and astringent taste. Spirituous liquors are often sweet¬ 
ened with it, and thus rendered more or less poisonous. It is 
also used to remove the rancidity of oils. Inferior olive oil is 
thus made to pass for good. 

335. Subacetate of copper, verdigris, is made by spreading 
the marc of grapes upon plates of copper exposed to the air 
for several weeks, or by spreading on the copper plates pieces 
of cloth dipped in crude acetic acid. Verdigris is in masses of 
a pale green color, composed of a multitude of minute, silky 
crystals. It is a mixture of several acetates of copper ; one of 
these may be obtained by digesting in warm water; a second 
by boiling ; the third is found in the insoluble residue. A fine 
green ink may be prepared by boiling a mixture of 8 parts 
verdigris, with 1 of cream of tartar, and 8 of water. The so¬ 
lution is then passed through cloth and bottled for use. 

336. Citric acid is obtained in large quantities from the 
juice of limes and lemons It is found in many other fruits, 
as in gooseberries, currants, &c., in conjunction with malic 
acid (352). From these fruits it is separated by the aid of 
chalk, which forms with the acid citrate of lime. Sulphuric 
acid is then added, which takes the base lime, and liberates 


334. Write and explain the formula for acetate oflead. How is this salt pre¬ 
pared 1 Mention some of its properties. What use is often made of sugar of 

335. How is verdigris prepared ? What is said of its composition ? _ 

336. Write and explain the formula of citric acid. How is this acid obtained? 
State some of its properties. 


II* 





250 


ELEMENTS OF CHEMISTRY. 


the citric acid. It is clarified by digestion with animal char¬ 
coal, and yields colorless, prismatic crystals, of a pure and 
agreeable acid taste, and soluble both in hot and cold water. 
These crystals are of two different forms ; those which sepa¬ 
rate in the cold by spontaneous evaporation contain 5 eq. of 
water, but those which are deposited from a hot solution con¬ 
tain only 4 eq. Their solution strongly reddens litmus, and, 
when long kept, is subject to spontaneous change. 

337. Malic acid is obtained from sour apples, pears, berries 
of the mountain ash, and many other plants. It may be pre¬ 
pared from the stalks of rhubarb, in which it occurs with oxa¬ 
late of potash. It is very deliquescent, and, therefore, difficult 
to crystallized It is colorless, and soluble in water. Alcohol 
also dissolves it. The aqueous solution has an agreeable acid 
taste, but becomes mouldy and spoils by keeping. Malic, citric, 
and tartaric acids, are found associated in almost all acid fruits. 

338. Tannic and gallic acids are substances in which the 
acid character is much less marked than in the preceding 
bodies. They constitute the astringent principles of plants, and 
are widely diffused throughout the vegetable kingdom. Tan¬ 
nic acid has been divided into several varieties, for, when pro¬ 
cured from certain vegetables, it affords a black precipitate with 
a salt of sesquioxide of iron, but when obtained from other veg¬ 
etables, it produces a green or grayish-green precipitate with the 
same salt of iron. As this acid refuses to crystallize, it has not 
yet been decided whether these are in fact different varieties, 
for the color of bodies is so much affected by external causes 
that it cannot be relied on as a proof of identity or difference. 

Tannic acid forms insoluble compounds with starch, gela¬ 
tine (411), and other organic bodies, which thus acquire the 
property of resisting putrefaction. When the skins of ani¬ 
mals are steeped in an infusion of oak bark or of any other 
vegetable containing tannic acid, the insoluble compound 
formed by the gelatine of the skin with the tannic acid consti¬ 
tutes leather. Quick tanning is performed by forcing the 
liquid containing tannin into the skin by pressure. The for¬ 
mation of leather may also be hastened by using a strong solu¬ 
tion ofthe tanning principle (which may be extracted from the 
bark), instead of the bark itself. But these quick methods do 
not produce equally good leather. The common method is to 
infuse coarsely powdered oak-bark in water, and to keep the 


337. Write and explain the formula of malic acid. Where is this acid found ? 
State its properties. 

338. Write and explain the formula for tannic and gallic acids. What 



ORGANIC CHEMISTRY. 


251 


Fig. 100. 


skin immersed in this solution a certain length of time. Dur¬ 
ing this process, which is slow and gradual, the skin is found 
to have increased in weight, and to have acquired considerable 
tenacity, and impermeability to water. Certain salts are also 
sometimes used in converting skins to leather. This is most, 
frequently done by laying them in a solution of alum and 
common salt. The leather prepared in this way is white and 
more supple than that prepared by the former method. 

Tannic acid of the oak may be prepared from nut-galls. A 
glass vessel a , (Fig. 100.) is loosely stopped with 
cotton or wool at its lower extremity, and half or 
two-thirds filled with powdered galls. Ether con¬ 
taining, as it invariably does, a little water, is 
poured upon the powder, and the vessel loosely 
stopped. The liquid, which after some time col¬ 
lects in the receiver below, consists of two distinct 
strata, b and c, of which the lowest, c, is a very 
strong amber or almost colorless solution of nearly 
pure tannic acid in water ; the upper, 6, consists of 
ether, holding in solution gallic acid, coloring 
matter, and other impurities. The solution of tan¬ 
nic acid, after being carefully separated, is dried in 
vacuo with the presence of sulphuric acid. The 
dry tannic acid thus produced is a slightly yellowish, 
friable, porous mass, without the slightest tendency 
to crystallize. It is very soluble in water, less so 
in alcohol, and very slightly soluble in ether. It reddens lit¬ 
mus, and possesses a pure astringent taste without bitterness. 

339. Gallic acid is much less abundant than tannic acid, 
and seems to be produced by an alteration of the latter. A 
solution of tannic acid when exposed to the air, gradually ab¬ 
sorbs oxygen and deposits crystals of gallic acid. The simplest 
method of preparing this acid in quantity is to make powdered 
nutgalls into a paste with water, and expose the mixture to 
the air in a w'arm situation for two or three months, adding 
water from time to time to replace that which is lost by dry¬ 
ing up. The mouldy, dark colored mass produced, may be 
strongly pressed in a cloth, and the solid portion boiled in a 
considerable quantity of water. The filtered solution deposits, 
on cooling, abundance of gallic acid, which may be drained and 
pressed, and finally purified by recrystallization. It forms 
small, feathery, and nearly colorless crystals, which have a 



is said of these acids? In what way is leather prepared? Explain Figure 
339. How is gallic acid prepared ? What are the properties of this acid ? 




252 


ELEMENTS OF CHEMISTRY. 


beautiful, silky lustre, and require for solution 100 parts of 
cold, but only 3 of boiling water. The solution has an acid 
and astringent taste, and is gradually decomposed by keeping. 
Like tannic acid it yields no precipitate with a protosalt of iron, 
but forms a deep black precipitate with a persalt, which dis¬ 
appears when the liquid is heated, by the reduction of the per¬ 
oxide of iron to the protoxide. This acid does not, like the 
last, tan the skin of animals. 

SECT. I. -3. FERMENTATION. 

340. Fermentation is a peculiar change which many organic 

substances, under the influence of air, moisture and warmth, 
undergo, the nature of which is not fully understood. It is 
always propagated from bodies containing nitrogen, but never 
spontaneously occurs in bodies destitute of this element. The 
ferment is a microscopic body of an oval form, having an en¬ 
velope of cellulose, and containing a liquid out of which 
granules are produced until the liquid is in this way exhausted. 
Two varieties of ferments are observed at different tempera¬ 
tures. That which is developed at a temperature below 45° 
is called the inferior leaven or ferment, and differs greatly 
from that which is formed at a higher temperature, and which 
is called the superior ferment. The latter increases in size, 
from a mere point barely perceptible by the microscope, to a 
diameter of about of an inch. The former attains a 

diameter of about of an inch. The superior ferment in¬ 
creases by the addition of a series of globules to each other, 
by developing the second out of the first, the third out of the 
second, &c. The inferior leaven consists of isolated globules. 
These, if the temperature is raised to 70° or 80°, develop glo¬ 
bules on one side, and are changed into the superior leaven. 
The inferior leaven often requires two or three months to com¬ 
plete the fermentation, and does not rise to the surface of the 
liquid like the superior leaven. 

341. By fermentation starch and gum are converted into 
sugar. This is called the saccharine fermentation. When 
the process is carried further, the sugar is converted into alco¬ 
hol and carbonic acid (345), which is called the vinous* fer- 

* Latin, vinum, wine, which in this case represents the alcoholic liquors. 


340. From what is fermentation always propagated ? What is the form of 
the ferment ? What are the two varieties of ferments called ? In what re¬ 
spects do they differ ? 

341. What is saccharine fermentation ?—vinous fermentation ’—acetous fer¬ 
mentation ? 




ORGANIC CHEMISTRY. 


253 


mentation. When alcohol is converted into vinegar (333), 
this is distinguished as the acetous, fermentation. There are 
several other kinds of less importance. 

342. Saccharine fermentation. The conversion of starch 
into dextrine, and afterwards into sugar, may be illustrated by 
the following experiment ‘—Boil two parts of potato starch 
with twenty parts of water, and add to the paste thus formed 
one part of gluten (410) of wheat flour. Expose the mixture 
for 8 hours to a temperature of from 122° to 167°. It will 
lose its pasty character, and become by degrees limpid, trans¬ 
parent, and sweet, passing first into dextrine and then into 
sugar. This production takes place in the germination and 
kiln-drying of malt. The mashing of the brewer, and the 
sweetening of bread in baking depend upon the same princi¬ 
ples. An analogous process takes place in the cooking of cer¬ 
tain vegetables, as parsnips, carrots, potatoes, &c., in which 
sweetness is developed by heat and moisture (p. 248). The 
saccharine fermentation of seeds in the manufacture of malt, 
is produced by the following process : Barley is first soaked in 
water for two or three days. The water is afterwards drained 
off, and the grain left in this moist state soon heats spontane¬ 
ously, swells, bursts, sweetens, and finally sprouts. When 
these sprouts are about an inch long, the process is stopped by 
putting the grain into a kiln, where it is well dried at a gentle 
heat. It is now malt , a crispy and friable substance, which is 
used in the manufacture of beer. 

343. In the manufacture of sugar from the cane, great 
difficulty arises from the extreme susceptibility of change in 
the cane juice. The latter, as it runs from the crushing mill, 
is as clear and colorless as water, but decomposition soon com¬ 
mences, which is accelerated by the heat and moisture of the 
climate, and in a short time the sweet tasted, bland liquid, be¬ 
comes converted into a spirituous or acescent product, turbid 
from insoluble, suspended matter, and totally unfit for the pur¬ 
poses to which it was intended to be applied. To guard 
against this evil, the sugar-boiler always endeavors to conduct 
the first part at least of the process as rapidly as possible. 
After the cane-juice is extracted by pressing the canes between 
two cvlinders of iron, it is then carefully boiled with lime- 
water" which neutralizes any free acid, and facilitates also the 


, 342. By what experiment may the conversion of starch into dextrine and af¬ 
terwards into sugar be illustrated ? How is the saccharine fermentation of 
seeds in the manufacture of malt produced ? * 

343. Describe the process by which raw sugar is manufactured ; by which 
sugar is refined. 



254 


ELEMENTS OF CHEMISTRY. 


separation of certain vegetable matters which rise in a thick 
scum to the surface. This is skimmed off, and the sugar, 
when thus clarified and sufficiently concentrated, is let off into 
shallow, wooden coolers, where it concretes. It is then put 
into barrels with holes in the bottom, through which a quantity 
of treacle, or molasses, gradually drips, and the sugar, after re¬ 
maining in these barrels for some weeks, becomes dry and fit 
for shipment. This is brown or raw sugar. 

The refining of sugar is usually performed in the foreign 
ports to which it is shipped. For this purpose it is put into a 
copper pan or boiler, previously charged with a certain quan¬ 
tity of lime-water, with which a portion of bullock’s blood has 
been well mixed by agitation, and also from 5 to 20 per cent, 
of bone-black (animal charcoal). In this state it is suffered to 
remain over night. Early in the morning fires are lighted 
under the pans, and, when the liquid boils, the coagulated al¬ 
bumen (409) of the blood rises to the surface, and carries the 
impurities of the sugar with it. Whites of eggs, which also 
contain albumen, are sometimes used instead of blood. The 
liquid is kept gently simmering and continually skimmed, until 
a small quantity taken out in a spoon appears perfectly trans¬ 
parent. This generally takes from 4 to 5 hours. The clear 
sirup is then boiled down as rapidly as possible, till a small 
quantity on the thumb is capable of being drawn out into 
threads by the fore finger. The more rapidly the boiling is 
effected without scorching the sugar, the better and greater 
is the product of the sugar. As this object is best accom¬ 
plished in a vacuum, hence the advantage of the vacuum 'pro¬ 
cess by which the sugar is boiled at a much lower tempera¬ 
ture (26), than when the process is conducted under the full 
pressure of the atmosphere. When the pressure within the 
boiler is only about that of the atmosphere, the sirup boils 
at only 115°; when it is about -i it boils at 175°. A larger 
product of refined sugar is in this way obtained from the raw 
material, because, at a high temperature, sugar rapidly under¬ 
goes a change, and is converted into molasses, and uncrystal- 
lizable sugar. The fire is now damped, and the sirup carried 
off in basins to the coolers. Here it is violently agitated with 
wooden oars till it appears granulated, for it is upon this agi¬ 
tation that the whiteness and fineness of the grain in the re¬ 
fined sugar principally depend. This breaks down the crys¬ 
tals while forming, and converts the whole into a granular 
mass. Sugar in this form permits the colored liquid contain¬ 
ing molasses, &c., to run off, which would be combined with 
the solid were it suffered to form in large crystals. 


ORGANIC CHEMISTRY. 


255 


This granular texture also facilitates the next process, which 
is to form the sugar into loaves and to purify these loaves. 
While still warm the sugar is poured into conical moulds, 
which are inverted, and upon the base thus placed uppermost, 
clay wet up with water is poured. The water from this clay 
gradually trickles through the sugar loaves and carries off the 
coloring matter, which is much more soluble than the crystal¬ 
lized sugar. The loaves thus rendered white are stove-clried at 
a temperature between 95° and 100°. The sirup or drainings 
collected in pots are mixed with the raw sugar in the next 
boiling. This syrup is divided according to its fineness, that 
which drains last from the sugar being, of course, the finest. 
The first runnings are reserved for the coarsest loaves, while 
the last, being little else than clear sirup, are boiled into loaves 
of the same fineness as those from which they ran. 

Between sugar candy and loaf sugar there is the same dif¬ 
ference as between calcareous spar and white marble. Large 
and distinct crystals characterize the former ; a confused as¬ 
semblage of small crystals the latter. Sugar candy is made 
without agitation of the hot sirup. This is poured into pans, 
across which threads are strung, and to these the crystals at¬ 
tach themselves. The pans are set in a stove, and great care 
is taken not to disturb the liquid, as upon this depends the 
largeness and beauty of the crystals. In this state the sugar 
is left for five or six days, exposed to a heat of about 95°. The 
crystallized candy is then taken out and washed with lime- 
water. This takes off the molasses from the outside , but a 
great quantity is enclosed within the crystals. 

344. Vinous fermentation. A solution of sugar in water 
may be kept for a comparatively long time without undergoing 
any change, but if blood, albumen, leaven, or any nitrogenized 
matters, in the act of decomposition , are mixed with it at a 
temperature of 70°, the sugar is rapidly decomposed first into 
grape sugar and then into carbonic acid C0 2 , and alcohol 
C 4 H 6 0 2 , as follows : 


CjaHj jOj x =cane sugar (320). 

f Add HO or water. J 

C 12 H 12 0 12 =grape sugar (320). 

Divide this formula into 2 [C.H.O ]4-4LC02]. 

2 (C,H fi 0 o ) = 2 eq. of Alcohol. 

' 4 b remains in solution. 

4 (CO ) =4 eq. of Carbonic acid. 

' 2 ' ' [passes off as gas.] 

The same action takes place in making bread. 


The leaven 


344. What must generally precede the vinous fermentation ? Explain the 





• 256 


ELEMENTS OF CHEMISTRY. 


acts chiefly upon the starch, sugar, and gluten (240) of the 
flour, changing the first to sugar, and then, with the sugar 
and gluten previously existing in the flour, into alcohol and 
carbonic acid. These rising and becoming entangled in the 
mass of the dough render it light. If the fermentation is car* 
ried too far, acetic and lactic (240) acids are formed, which 
render the bread sour. This may be remedied by adding car¬ 
bonate of soda or of magnesia, which neutralize the acids in 
the dough, and form harmless salts. The use of leaven is to 
hasten the fermentation of the bread , and to equalize the pro¬ 
cess throughout the mass of the dough. Were the latter fer¬ 
mented without the use of leaven, not only would the process 
be much longer, but a portion of the dough would pass into 
the acetous and lactic fermentation before the remainder had 
become sufficiently fermented to be light. 

Dough is often raised without a ferment by carbonate of 
ammonia, or bicarbonate of soda. When carbonate of ammo¬ 
nia is used, both the carbonic acid and the ammonia are ex¬ 
pelled by the heat of baking, except the small portions which 
become entangled in the mass of the dough. When bicarbo¬ 
nate of soda is used, dilute hydrochloric acid (muriatic acid) 
is afterwards added to the dough. The hydrochloric acid 
unites with the soda (sodium) and liberates the carbonic acid. 
By the action of hydrochloric acid on the soda, chloride of 
sodium or common salt is formed. 

345. The sugar of fruits by fermentation is converted into 
different alcoholic liquors. The peculiar and characteristic 
taste of these different liquors is produced by the substances 
which are present with the sugar, and not by the fermented 
sugar itself. The amount of liquor produced must, of course, 
be in proportion to the sugar which the plant contains, but 
this is not the only circumstance which determines the plant 
or fruit to be selected. The manner and proportion in which 
the sugar is mixed with the other ingredients, is what chiefly 
determines the quality and value of the liquor produced. 
Hence, though the sugar cane yields sugar far more abundantly 
than any other"plant, and consequently may be made to pro¬ 
duce the most liquor, yet the grape is selected as producing 
the best wine. 

When the expressed juice of grapes, or must , is enclosed in 
a vessel out of contact of air, and subjected to the heat of 
boiling water, the small portion of oxygen present is rendered 


diagram. How is bread fermented and raised ? To what is the peculiar and 
characteristic taste of the different liquors owing ? How may fermentation be 
commenced in the expressed juice of cane ? How is it then continued ? Why 



ORGANIC CHEMISTRY. 


257 


inactive, and the liquor does not ferment. But an exceedingly 
small portion of oxygen, even a single bubble, will start the 
fermentation, after which it will go on with or without the 
presence of air. The mutual reaction of the ferment formed 
on the introduction of the bubble of oxygen, and the sugar oT 
the grape juice, produces alcohol and carbonic acid, or, in other 
words, excites and continues fermentation. Yeasty particles 
are evolved and float in the liquid. If a solution of pure 
sugar he added, it is involved in the change, and portion after 
portion will disappear, but finally the yeast itself is exhausted, 
and then any excess of sugar remains unacted upon. 

Most sweet substances pass spontaneously into fermentation 
without the necessity of adding to them a ferment, because 
they contain besides sugar, one of the nitrogenized substances, 
albumen, caseine, or gluten (408 and 410). Thus from cur¬ 
rants, gooseberries, beets, and grapes, wine is prepared, cider 
from apples, &c. New beer holds some sugar and gluten in 
solution, therefore, like wine and cider, it undergoes, when 
kept, a slight fermentation. If this is allowed to take place 
in well-stopped bottles, so that the carbonic acid cannot escape, 
a foaming beer (bottled beer) is obtained. In the ‘same way 
bottled cider and champagne are made. 

346. The circumstances which promote the vinous fermen¬ 
tation, are the following :—(1.) The presence of the proper 
quantity of active yeast. If in the course of a slack fermen¬ 
tation the yeast subsides to the bottom, the fermentation ceases, 
but may be excited anew by stirring up the ingredients. (2.) A 
certain degree of warmth. This should not be less than 51° 
nor more than 86°. The temperature of 68° to 77° is the 
most favorable to the commencement and progress of the fer¬ 
mentation. Other circumstances being the same, the rapidity 
of the fermentation is proportional to the temperature within 
certain limits, so that by changing the temperature, the action 
may be altered at pleasure. (3.) The fermentation proceeds the 
better and more equally the greater the mass of fermenting 
liquor , probably on account of the uniformly high temperature, 
as well as the uniform distribution of the active properties of 
yeast, by the greater energy of the movements of the liquid. 
(4.) The presence of water. When the saccharine solution is 
too much concentrated it does not ferment. Hence, very 


do all sweet substances pass spontaneously into fermentation ? How are bot¬ 
tled cider, beer, and wine prepared ? Why do these liquors foam on remov¬ 
ing the cork ? 

346. Mention some of the circumstances which promote the vinous fermen¬ 
tation. 



258 


ELEMENTS OF CHEMISTRY. 


sweet musts furnish wines containing much undecomposed 
sugar. For a complete fermentative action, one part of sugar 
should be dissolved in ten parts of water. 

^ 347. Fermentation may be tempered or stopped :—(1.) 
By those means which render the yeast inoperative. This 
effect is produced particularly by oils that contain sulphur, as 
oil of mustard. It is produced also by sulphuric and sulphur¬ 
ous acids and by very many organic acids. Fermentation is 
checked by alcohol itself when sufficiently concentrated. No 
fermented liquor can contain more than 25 per cent, of absolute 
alcohol. (2.) By the separation of the yeast. This may be 
done by filtration or subsidence. (3.) By lowering the tem¬ 
perature to about 45°. (4.) By excluding the air. 

348. Pure alcohol is a colorless liquid, of pungent and agree¬ 
able taste and odor. At 60° its sp. gr. is 0.794 ; that of its 
vapor 1.613. When alcohol is obtained from sugar, carbonic 
acid escapes, carrying off a portion of the carbon and oxygen 
of the sugar. Alcohol, therefore, contains less carbon and oxy¬ 
gen than sugar, and consequently more hydrogen. To this 
is owing its lightness, its great inflammability, and its pale- 
bluish flame. This flame is free from smoke, and the pro¬ 
ducts of its combustion are carbonic acid and water. It is of 
great use in chemical investigations, as it deposits no carbon 
or any other substance on bodies exposed to its heat. Alcohol 
boils at 173°, and at a still lower point if slightly diluted with 
water, though the boiling point rises if the water be in greater 
proportion. It has never been frozen. Even at a cold of— 
148° it remains fluid. It is, therefore, excellently adapted for 
thermometers, by which great degrees of cold are to be meas¬ 
ured. It is also used in the gas pipes of cities to prevent the 
freezing of the water which settles in them. The illuminating 
gas is sometimes made to pass through alcohol, by which not 
only is most of the steam withdrawn from the gas, but so much 
vapor of alcohol is also added to what remains, that the con¬ 
densed liquid-of alcohol and water in the gas-pipes does not 
freeze in winter. The specific gravity of alcohol varies with 
the amount of water present ; hence its purity may be deter¬ 
mined by ascertaining its density It is miscible with water 
in all proportions, and has even a great attraction for it, ab- | 
sorbing its vapor from the air, and abstracting the moisture ; 
from membranes and from most organic substances which are 
immersed in it. It preserves bodies from decay by withdraw¬ 
ing water from them, and by excluding the air. 

347. By what means may the vinous fermentation be regulated or stopped ? 

348. Mention some of the properties of pure alcohol. 





ORGANIC CHEMISTRY. 


259 


The solvent powers of alcohol are of great use ; it is employed 
d dissolve resins, oils, and other bodies not acted on by water, 
ffie gases are dissolved by alcohol generally in greater propor- 
ion than by water. Its vapor with oxygen gas forms an ex- 
ilosive mixture which may be fired by the electric spark. 
4any salts which have been dissolved in alcohol on crystalliz- 
ng retain a portion of the alcohol, in a state analogous to that 
f the water of crystallization in other salts. In some of these 
he alcohol is retained by an affinity so strong that it is not 
xpelled under a temperature of 400° or 500°. Wine, beer, 
ec., owe their intoxicating properties to the alcohol which they 
;ontain, the quantity of which in these liquors varies very 
nuch ; they owe peculiar smell to exceedingly small quantities 
if bodies analogous to the volatile oils (374). In wine it 
imounts on an average, to only about part and yet a 

lifference may be perceived in the smell of different kinds of 
vine. Port and sherry, and some other strong wines, contain 
rom 19 to 25 per cent, of alcohol, while in the lighter wines 
)f France and Germany, it sometimes falls as low as 12 per 
sent. Beer, porter, &c., contain from 3 to 10 per cent. 

349. When the alcoholic liquid is wine the product of the 
listillation is brandy, which consists chiefly of a mixture of al- 
;ohol and water. If a little port wine, for example, be dis¬ 
tilled at a moderate heat, brandy will be distilled over sepa¬ 
rate from the other constituents of the wine, and, by subsequent 
listillation at a still lower heat, the alcohol of the brandy may 
be separated from its water. It is, therefore, like alcohol, 
colorless in its pure state. Its ordinary yellow or red color is 
obtained from the coloring matter of the new oaken casks in 
which it is kept. A little burnt sugar is sometimes added to 
improve its tint, or to give it the desired color when it does not 
acquire a tint from the cask in which it is kept. 

350. Rum is distilled from the sugar cane. After most of 
the juice has been pressed out for making sugar, what still re¬ 
mains in the brqised cane is extracted by water, and this 
watery solution of sugar is fermented and produces rum. 
Both the fermenting and the flavoring principle reside chiefly 
in the fresh cane-juice, for they are dissipated to a great extent 
by boiling the sirup. Spirits distilled from West India molasses 
are perfectly free from any flavor of rum. Bum is yielded in 
very large quantities even from the ivash of the cane, owing 
to the great amount of sugar which it contains. 


349. Of what is brandy composed ? In what way may the difference be- 
reen port wine, brandy, and alcohol be shown ? To what is the color of 
andy owing 1 What is sometimes added to improve its tint l 

350. How is rum manufactured ? 





260 


ELEMENTS OF CHEMISTRY. 


351. Gin is distilled from rye. To every 100 gallons of the 
liquor thus formed, two pounds of juniper berries, from three 
to five years old, are added, to which is owing the peculiar 
flavor of gin. About one-quarter pound of salt is added at the 
same time, and the whole is put into a still, and the spirit dis¬ 
tilled over by a gentle and well-regulated heat. 

352. Cider is best obtained from bitter apples, which afford 
a denser juice, richer in sugar, which clarifies well, and when 
fermented keeps a long time. The juice of sweet apples is 
difficult to 'clarify, and that of sour apples makes bad cider. 
Late apples are in general preferred. After these are gather¬ 
ed, they are kept for about fifteen days to become mellow, 
which diminishes their mucilage, and develops alcohol and 
carbonic acid. The fruit should be gathered in dry weather. 
Much water is contained in the juice of apples. There is also 
found a little sugar analogous to that of the grape, a matter 
capable of causing fermentation in contact with the air, a 
pretty large proportion of mucilage, with malic and acetic 
acids. 

SECT. I.-4. CONVERSION OF ALCOHOL INTO ETHER. 

353. When 5 parts of strong alcohol are mixed with 9 parts 
of sulphuric acid, and the mixture heated to boiling, sulphovinic 
acid (an acid ether) is formed at first, and this, at a somewhat 
higher heat, is decomposed into ether and water. The final 
result may be expressed as follows : 

C.H ,0„ = alcohol. 

Divide this formula inl6 C H O-J-HO, 

C 4 H 5 0 = Etiier. 4 

[distilled from gulp, acid and alcohol ] 

HO= Water. 

[distilled with the ether.] 

Ether, when pure, is a colorless transparent liquid of a pe¬ 
culiar taste and odor. Its specific gravity at 60° is about 
0.720. It boils at 96°. At 46° below zero it freezes, and 
shoots into crystals. When dropped on the hand it occasions a 
sharp sensation of cold, from its rapid evaporation. It is more 
combustible, and burns with the evolution of more light than 
alcohol. It is exceedingly volatile, and the mixture of its va¬ 
por with the air is highly explosive. For this reason bottles 
containing ether should never be opened near a flame, as the 
mixed air and ether vapor within might explode and blow up 


351. How is gin obtained? 

352. What kind of apples afford the best cider ? Why are bitter apples to 

be preferred to sweet or to sour apples ? : 

353. How is alcohol converted into ether ? State some of the properties of 
ether. 



ORGANIC CHEMISTRY. 


261 


the bottle. The same precautions should be observed with re¬ 
gard to alcohol, and the compounds of alcohol and turpentine 
(burning-fluid, spirit-gas, chemical oil, &c.) When ether 
vapor is mixed with oxygen and fired, it explodes with the ut¬ 
most violence. When kept in an imperfectly stopped vessel, 
ether becomes acid, producing acetic acid by absorbing oxygen 
from the air. This attraction for oxygen is increased by eleva¬ 
tion of temperature. Ether is miscible with alcohol in all pro¬ 
portions, but not with water. It dissolves only to a small ex¬ 
tent in water (10 of water to 1 of ether), and may be sepa¬ 
rated from alcohol by the addition of water. In this manner 
commercial ether may be examined. The solvent powers of 
ether are much less than those of alcohol or water. It is, 
however, of considerable use in organic chemistry in dissolving 
many oils and fatty substances. It also dissolves phosphorus 
to a small extent, and a few saline compounds, and some or¬ 
ganic principles. 

SECT. I. -5. ACTION OF HEAT ON VEGETABLE TISStE. 

354. Among the products obtained when wood is subjected 
to dry distillation are : (1.) Charcoal, which remains behind 
after the volatile portions are driven off; (2.) A mixture of 
carburetted hydrogen, carbonic acid, and carbonic oxide gases, 
which are always produced in the manufacture of illuminating 
gas : (3.) Wood-vinegar, or pyroligneous acid which redis¬ 
tilled very slowly gives pyroxilic or wood spirit. From the 
latter chloroform may be and often is obtained by distillation 
with chloride of lime. (4.) Wood-tar , a thick brown resinous 
liquid. Of these products, charcoal and illuminating gas have 
|been already considered ; wood-vinegar and wood-tar alone re¬ 
gain to be described. 

355. Wood-vinegar, pyroligneous acid. One pound of dry 
!beech wood yields nearly half a pound of pyroligneous acid. 
In its crude state it has a brownish black color, owing to the 
! tar which it holds in solution, and a smoky odor, together with 
1 very acid and disagreeable flavor. When purified it furnishes 
i strong acetic acid, which on account of its cheapness, is now 
nuch used in the preparation of acetates, particularly such as 
ire employed in calico printing, and in dyeing. It possesses 
Powerful antiseptic properties. Fresh beef dipped in pyroligne¬ 
ous acid in the summer season, for the space of only a minute, 

| was perfectly fresh in the following spring. The same 


354. Mention some of the products obtained by the distillation of wood. 




262 


ELEMENTS OF CHEMISTRY. 


effect is produced by soaking animal substances in pyroligneous 
acid for a short time as by suspending them for months in 
smoke. • 

Wood-vinegar owes its antiseptic properties to a peculiar 
substance called creosote ; one pound of wood-vinegar contains 
a quarter of an ounce of creosote in solution. Pure creosote 
is a colorless oleaginous liquid, gradually becoming brown by 
age, and of an oily consistence. It has a strong smell of 
smoke, and a burning taste, which disorganizes the tender 
skin of the tongue or the mouth. When taken internally it 
is a powerful poison. When applied for the tooth-ache, it is 
usually mixed with oil of cloves, and also with alcohol, other¬ 
wise its action would be too corrosive. No antidote is known 
to the poisonous effects of creosote, but its presence is easily 
detected after death by its peculiar and penetrating smell. 

356. Chloroform , 0 2 HC1 3 . By whatever method^this 
substance is prepared, it is liable to be contaminated with 
impurities, which render it highly injurious to the system, 
and in some cases fatal. The only chloroform which is proper 
for use, is that obtained by the action of hypochlorite of lime 
upon alcohol, which has also been carefully rectified by distill¬ 
ation. As thus prepared, chloroform is a limpid, colorless 
liquid, volatile, and having a bland ethereal odor, and a hot, 
aromatic, sweet taste. Its density is 1-5, and it boils at 141°. 
It is nearly insoluble in water, and is not affected by concen¬ 
trated sulphuric acid, but dissolves readily in alcohol and 
ether. It is lighted with difficulty, and burns with a green 
flame. Chloroform has extensive solvent powers, being capa¬ 
ble of dissolving caoutchouc, gutta-percha, lac, amber, and 
copal, substances which resist most other solvents. It also 
dissolves iodine, bromine, the organic alkalies, volatile oils, 
resins, wax and fats. The principal use of chloroform is in 
medicine,. where it is used both externally and internally. It 
is most commonly inhaled , when it produces a loss of con¬ 
sciousness, especially a total insensibility to the agents which 
ordinarily produce acute pain. This insensibility is generally 
produced in one or two minutes, and continues for five or ten 
minutes; but the effect may be kept up for many hours, by 
renewing the inhalation from time to time. The use of 
chloroform is followed by a drowsy state, or by quiet sleep, 
and no recollection is retained of anything that occurred dur- 


355. What is said of pyroligneous acid ? To what does this acid owe its 
antiseptic properties 1 State some of the properties of creosote. 

356. Write the composition of chloroform. How is this substance produc¬ 
ed 1 Mention some of its properties ;—some of its uses. 



ORGANIC CHEMISTRY. 


263 


ing the state of insensibility. When rapidly inhaled with a 
free supply of air , it retards the circulation of the blood ; 
when slowly inhaled, it produces highly injurious effects, dis¬ 
organizing the blood, and stopping the circulation in the cap¬ 
illaries. Bromine and iodine form two analogous compounds, 
bromoform C ? HBr 3 and iodoform C 2 HI 3 . 

Wood-tar is of a resinous nature, being, like the resins, in¬ 
soluble in water, though soluble in alcohol. It is very rich in 
carbon, as is, in some degree, indicated by its black color. On 
distillation it separates into a volatile oil (oil of tar), and a 
black pitch, which is not volatile. When ships are calked or 
tarred, the tar undergoes a similar change, the oil volatilizes 
and the pitch hardening in the pores of the wood, prevents 
' the penetration of water. The wood is kept dry by this pro¬ 
cess, and, therefore, is less liable to decay. It is also preserved 
by the creosote which the tar contains. 

SEC. I.-6. ORIGIN OF SOILS-HUMUS. 

357. Origin of soils. —The following eleven substances 
may be regarded as the proximate elements of soils : silica, 
alumina, lime, potash, soda, magnesia, oxide of iron, oxide of 
manganese, phosphoric acid, sulphuric acid, and chlorine. Al¬ 
most all soils, in their primitive state , are chiefly made up of 
these elements ; for the vast rock formations of the globe, 
by the decomposition of which soils are formed, are composed 
almost entirely of but very few mineral ingredients, and 
these minerals are almost wholly composed of the elements 
above mentioned. These primitive soils have, however, been 
subjected to a great variety of changes from the constant 
action of water, the cultivation of crops, and the agency of 
great geological causes in past ages, yet no other leading 
inorganic constituent* of the soil is found besides those above 
mentioned, although some of these are often wanting. 

The principal agents by which rocks are decomposed to 
form soils, are : first, the action of water in its liquid form, 
by its congelation in the crevices of rocks, and also by its 
solvent power, especially when containing carbonic acid; 
secondly, the carbonic acid of the atmosphere, which slowly 
but constantly decomposes the mineral ingredients of the 
rocks, particularly feldspar ; and, thirdly, the action of plants. 
Rocks at first barren and destitute of soil, are covered with 


357. What substances may be regarded as the proximate elements of soils ? 
I What are the principal agents by which rocks are decomposed ? How is the 
i organic part of the soil formed 1 




264 


ELEMENTS OF CHEMISTRY. 


mosses and lichens, which insinuate their roots into the smallest 
crevices, and, by their continued action, combined with the 
moisture which they carry into those crevices, they cause the 
rocks to cleave apart and crumble down, and thus form the 
inorganic constituents of the soils. These plants in time de¬ 
cay, and by their decomposition form the necessary organic 
part of the soil. Upon this new-made soil other plants re¬ 
quiring more nourishment, as the grapes, can take root and 
grow. Plants of this class exert a still more powerful decom¬ 
posing agency upon rocks, than that exerted by mosses and 
lichens,—the first vegetation. The layer of soil is in this way 
thickened, and made suitable for the growth of plants. 

358. The organic part of the soil thus formed, or vegetable 
mould, is commonly called humus, although that which 
characterizes humus is a vegetable called humic acid. This 
acid is a black substance, insoluble or nearly so in water, but 
very soluble in alkaline solutions. The principal agent o'f its 
solution in the soil is carbonate of ammonia, hence the ad¬ 
vantage of mixing with humus and turf, (for the latter, when 
exposed to air and moisture, forms a variety of humus,) ma¬ 
nures which contain, or, by decomposition, form carbonate of 
ammonia. In the formation of humic acid, by the decom¬ 
position of vegetable matter, carbonic acid is given off, by the 
union of the oxygen of the air with the carbon of the plant. 
This decomposition is carried on still farther, so that a soil 
abounding in humus furnishes plants both through their roots 
and through their leaves with an abundant supply of carbonic 
acid, and thus greatly increases the vigor of their growth. 
Water is at the same time formed in large quantity, by the 
union of the oxygen of the air with the hydrogen of the 
plant. 

359. The chemical process which takes place in the decay 
of vegetable matter, very much resembles*those changes which 
wood undergoes in combustion, except that it takes place far 
more slowly. What is effected by combustion in minutes, is 
produced by decay only in the course of years. In combus¬ 
tion the constituents of wood, by uniting with the oxygen of 
the air, are converted into carbonic acid and water. The 
same products are also formed in the decay of wood. In com¬ 
bustion, as well as in decay, the wood assumes a darker color, 
because in both cases the hydrogen is oxidized more rapidly 

358. What is humus?—humic acid? What is the principal agent of its 
solution in the soil ? What is given off in its formation ? 

359. What is said of the resemblance between the process of decay and 
that of combustion ? 



ORGANIC CHEMISTRY. 


265 


than the carbon, and the carbon which remains covers the 
burnt or decayed surface with first a brown, and then a black 
color. 

360. Humus possesses many properties of great value to 
plants. If a portion of garden soil is drained with water, so 
as to remove the soluble substances (almost all the organic 
substances, as well as a small part of the inorganic), this soil 
will entirely lose its fertility. If, on the other hand, some 
plants are placed in pure sand, and supplied with water 
charged with organic matter, they will grow vigorously. 
Humus improves the physical state of the soil, rendering it 
light, porous, and at the same time very absorbent and re¬ 
tentive of moisture and ammonia from the atmosphere, and 
less subject to variations of temperature. It also, from the 
dark color which it imparts to the soil, enables it to absorb a 
greater number of the sun’s rays. When moist, or even when 
covered with a certain depth of water, humus absorbs oxygen ; 
but when dry, or when covered with ice, this absorption does 
not take place by humus or by any other earthy element. 
This absorption of oxygen produces a chemical change upon 
humus, removing a part of its hydrogen to form water, and 
also carbon in the form of carbonic acid. When covered with 
water the hydrogen is chiefly removed, and the humus left 
in a carbonized state. In marshy countries this takes place 
to a very great extent. 

Humus also facilitates the solution of the carbonates and 
phosphates of lime and magnesia, and moderates and regu¬ 
lates the decomposition of putrefiable matter. Many of the 
above properties are possessed also by other elements of the 
soil, but by none in as great a degree as by humus. When 
rendered soluble by carbonate of ammonia, or by alkaline so¬ 
lutions, it is absorbed by the roots of plants, and, probably, 
assists directly in their nourishment. 

361. When there is more than 50 per cent, of organic 
matter in the soil, certain organic acids are generated, which 
are very injurious to plants. In boggy and peaty soils the pro¬ 
portion of organic matter is sometimes as high as 70 per cent. 
Such land is called sour , and produces nothing but poor wiry 
grass. On the other hand, a soil that contains less than one- 
half per cent, of organic matter will scarcely support vegeta¬ 
tion. In the best soils the proportion does not average 5 per 


360. How does humus affect the physical characters of soils ? When does 

it absorb oxygen ? , . „ . 

361 What effect does the presence of a very large quantity of organic 

12 




266 


ELEMENTS OF CHEMISTRY. 


cent., and rarely exceeds 10 or 12. Oats and rye will grow 
upon land containing only 1 to li per cent., barley where 
2 or 3 per cent, are present. Good wheat soils contain in 
general from 4 to 8 per cent. ; if very stiff and clayey, the 
proportion rises sometimes as high as 10 to 12 per cent. 

SECT. I. -7. OILS AND FATS. 

362. The vegetable and animal fats agree so closely, that 
it will be convenient to consider them under one head. The 
vegetable fats are usually found in seeds or fruits ; animal fats 
in a cellular membrance, called adipose tissue. The leaves 
of many plants are varnished on their upper surfaces with a 
covering of wax and fat. Plants of the order cruciferee (mus¬ 
tard, radish, water-cress, &c.), are especially oil-bearing spe- 
cjes. Oily bodies are divided into volatile and fixed. The 
former are capable of being distilled, without decomposition ; 
the latter are not. When dropped or spread on paper, they 
all leave a greasy stain, which disappears on applying heat 
if caused by a volatile oil, but remains if produced by a fixed 
fatty substance. All these bodies have an attraction for oxy¬ 
gen, which, in some cases, is so great as to occasion sponta¬ 
neous inflammation. Large masses of cotton and flax have 
taken fire from being moistened with rape or linseed oil (97.) 
The effect of this absorption of oxygen leads to a farther clas¬ 
sification of the fixed oils into drying and non-drying oils, or 
those which become hard and resinous on exposure to the air, 
and those which thicken slightly, become sour and rancid, but 
never solidify. To the first class belong the oils used in 
painting, as linseed, rape, poppy-seed and walnut : and to 
the second, olive and palm oils, and all the oils and fats of 
animal origin. 

363. The fixed oils in general have but a feeble odor, and 
scarcely any taste. Whenever an oil possesses any taste, it 
is invariably found to contain some volatile oily principle, as 
that of common butter. All the fixed oils are insoluble in 
water, and, with the exception of castor oil, but slightly solu¬ 
ble in alcohol. In ether, and in essential oils, they dissolve 
in large quantity. The consistence of these substances varies 


matter have upon soils 1 How large quantities of it are required by the 
various cultivated crops ? 

362. What is said of the sources of animal and vegetable fats ? Into what 
are oily substances divided ? What is said of the attraction of oils for oxy¬ 
gen ? Into what two classes are the fixed oils divided ? 

363. Mention some of the properties of the fixed oils. What is margarine ? 
—oleine 1 —stearine 1 In what way may these bodies be saponified 1 If the 



ORGANIC CHEMISTRY. 


267 


from that of the thinnest olive oil to that of compact suet. 
This difference proceeds from the variable proportion in which 
the solid and fluid principles are associated in the natural 
products. All these bodies may in fact be separated by mere 
mechanical means, and by exposure to cold, into two or three 
different substances, which dissolve or mix with each other in 
all proportions. Thus olive oil exposed to a cold of 40°, de¬ 
posits a large quantity of crystalline solid fat, which may 
be separated by filtration or pressure. This is termed mar¬ 
garine* from its pearly aspect. That portion of oil which 
retains its fluidity at this, or even a greater cold, has received 
the name of oleine, or elaine. Still another fatty principle 
has been obtained from solid animal fats, by pressure between 
the folds of blotting-paper. The paper becomes impregnated 
with a permanently fluid oil, or oleine, while the solid part is 
found to consist of two solid fats, one resembling the margar¬ 
ine of olive oil, and the other having a much higher melting 
point, and other properties which distinguish it from that sub¬ 
stance. This is called stearine. f A solid crystalline sub¬ 
stance obtained from palm oil is called palmitine. 

When stearine, margarine and oleine are boiled with a 
strong solution of caustic potash or soda, they combine with 
these alkalies, and form soap.J If acid be added to the soap 
thus formed, the acid takes the alkali, and decomposes the 
soap. The fat which separates is found to have completely 
changed its character, having acquired a strong acid reaction 
when applied in the melted state to test-paper, and having 
become soluble with the greatest facility in warm alcohol. 
It is in fact a new substance, a true acid, capable of forming 
salts. This acid has been generated out of the elements of 
the neutral fat under the influence of the base . Stearine, 
when thus treated, yields stearic acid, margarine margaric 
acid , oloine oleic acid. Common animal fat gives a mixture 
of these three acids. Besides these acids produced in the 
process of saponification, a very peculiar sweet substance, 
called glycerine, remains in the solution after the acid has 
been removed. 

* Latin margarita, a pearl. 

+ Some fatty substances contain peculiar varieties of oleine, margarine, and 

stearine. . n . . , 77 

t Ammonia also forms with stearine, margarine, and oleine a soluble soap, 
and lime, baryta, strontia, pbotoxide of lead, and many other substances, in¬ 
soluble soap. The soap of lead is the ordinary lead plaster. _ 


soap thus formed is decomposed by the addition of acid, in what state is the 
fat obtained ? How has the acid fat been produced ? What three acids are 
in this way formed from stearine, margarine, and oleine ? What substance 
remains in the solution after these acids have been withdrawn l 





268 


ELEMENTS OF CHEMISTRY. 


364. Stearine and stearic acid. Pare stearine is most 
easily obtained by mixing- purified mutton fat. melted in a 
glass flask, with several times its weight of ether, and suffer¬ 
ing the whole to cool. Stearine crystallizes out while mar¬ 
garine and oleine remain in solution. The soft, pasty mass, 
may then be transferred to a cloth, strongly pressed, and the 
solid portion still further purified by re-crystallization from 
ether. It is a white, friable substance, insoluble in water, 
and nearly so in cold alcohol. Boiling spirit takes up a small 
quantity, and boiling ether dissolves it very easily, but when 
cold retains only of its weight ; hence, the process above 
given for obtaining stearine. The melting point of stearine, 
which is one of its most important physical characters, is 
about 143°. 

Stearic acid crystallizes from hot alcohol in milk-white 
needles, which are inodorous, tasteless, and quite insoluble, in 
water. It is harder and more brittle than wax, and melts at 
158° It dissolves in its own weight of cold alcohol, and in 
all proportions at a boiling heat. It is also soluble in ether. 
Alkaline carbonates are decomposed by stearic acid. It may 
be volatilized in a vacuum without change. Stearine (stearic 
acid) candles are now manufactured on a large scale. They 
have become of late so popular, that large factories have been 
erected for their preparation. The wick of these candles is 
plaited upon a braiding-machine, moistened with very dilute 
sulphuric acid, and dried. Wick prepared in this way is 
found to fall on one side as it burns, and to consume entirely 
without requiring to be snuffed. The formula for stearic acid 
isC sa H 66 O s ,2HO. 

365. Oleine and oleic acid. It is doubtful whether a per¬ 
fectly pure oleine has yet been obtained ; the separation of 
the last portions of margarine, with which it is always as¬ 
sociated, is extremely difficult. Any fluid oil, animal or 
vegetable, which has been carefully decolorized, and filtered 
at a temperature approaching the freezing point of water, 
may be taken as a representative of this substance. 

Oleic acid, in its external appearance, is hardly to be dis¬ 
tinguished from olive-oil, but it differs from this oil in havino- 
an acid taste and reaction, and in readily dissolving in cold 
alcohol. The oleic acid produced in stearic acid factories 
from tallow, as a secondary product, is frequently an article 

364. How is pure stearine most easily obtained ? Mention some of its prop¬ 
erties of stearic acid. What use is made of stearic acid ? Write the 
formula for stearic acid. 

365. What is said of oleine ?—oleic acid ? Write the formula for oleic acid. 




ORGANIC CHEMISTRY. 


269 


of commerce, being employed on account of its cheapness in 
the manufacture of soap, and in greasing wool for spinning. 
It melts at about 39°, and gives rise to a class of salts. The 
formula for oleic acid is C 36 H 33 0 3 , HO. The following 
table contains the proportions of oleine and stearine in some 
of the most common fats : 


Fresh butter in summer, 

Oleine. 

60, 

Stearine. 

40. 

winter, 

37, 

63. 

Hogs’ lard, 

62, 

38. 

Ox marrow, 

24, 

76. 

Goose fat, 

68, 

32. 

Duck fat, 

72, 

28. 

Ox tallow, 

25, 

75. 

Mutton suet, 

26, 

74. 


366. Margarine and margaric acid. Margarine very 
much resembles stearine ; it is however more fusible, melting 
at 113°, and very much more soluble in cold ether. Mar - 
garic acid closely resembles stearic acid ; it differs in its com¬ 
position, has a lower melting point (about 140°), and is more 
soluble in spirit. Its composition is C 34 H 33 0 3 H0. 

367. Butyrine and butyric acid. Common butter is 
formed of the fatty particles of milk, which unite into a solid, 
crystallizable, easily fusible fat; a fluid oily substance ; and 
a yellow coloring matter, besides mechanical impurities, as 
caseine (409). The oily part appears to be a mixture of 
oleine and several odoriferous principles, called butyrine , 
caprine, and caproine. Another principle, called butyroleine , 
is also formed in butter. The solid fat contains margarine, 
but stearine has not yet been found, and probably does not 
exist in butter. By saponification of butyrine, caprine, and 
caproine, butyric , capric, and caproic acids have been ob¬ 
tained. Another fatty acid has been found in butter, which 
is called the caprylic. The chemical composition of butter is 
therefore very complex. 

368. Glycerine. Oleine, margarine, and stearine are un¬ 
doubtedly compounds of oleic, margaric, and stearic acids, 
with a body called glycerine , (from G-reek, glulcus, sweet.) 
This is the sweet principle of fatty substances. When ex- 


366. What is said of margarine and margaric acid ? Write the formula of 
margaric acid ? 

367. Of what does butter consist? What substances are obtained by the 
saponification of butyrine ? 

368. What is glycerine ? Mention some of its properties. 



270 


ELEMENTS OF CHEMISTRY. 


tracted from these it is a transparent liquid, without color or 
smell, and of a sirupy consistence. Its taste is very sweet. 
When thrown on burning coals it takes fire, and burns like 
oil. Water combines with it in almost all proportions ; alco¬ 
hol dissolves it readily ; nitric acid converts it into oxalic 
acid. Its formula isC 6 H 8 O e . 

369. Wax. Common bees-wax, freed from its yellow color¬ 
ing matter by bleaching, (p. 49,) may be separated by boiling 
alcohol into three different substances, cerotic acid, myricine, 
and ceroline. Cerotic acid is a white, crystalline substance, 
soluble in about 16 parts of boiling spirit, and melting at 
172°. Myricine is much less soluble in alcohol, and melts at 
162°. 

Wax occurs in small quantities in all plants, especially in 
the shining coating of the leaves, stalk and fruits. It is very 
apparent in the skin of apples, and the pollen of flowers. 
Some plants of Japan and South America contain large quan¬ 
tities of wax, and from these it is extracted by boiling and 
pressure. This is found in commerce under the name of 
Japan wax. The wax myrtle grows in almost all parts 
of the United States. The berries of this plant, which grow 
in clusters closely attached to the stems and branches, are 
covered with a coating of wax. These are boiled in water, 
and the wax, melting and floating on the surface, is either 
Skimmed off and strained, or allowed to concrete as the liquor 
cools, and removed in the solid state. To render it pure, it is 
again melted and strained, and then cast into large cakes. It 
is collected in New Jersey, but more abundantly in New 
England, particularly Rhode Island, whence it is exported 
to other parts of the country. 

370. Cetine, spermaceti , is obtained from the head of 
the spermaceti whale. The soft, solid matter found here is 
subjected to pressure, by which it is separated into a fluid oil, 
and a crystalline brownish substance. The latter, when 
purified, becomes the snow-white spermaceti of commerce. 
It melts at 120°, and, when cooled under favorable circum¬ 
stances, forms distinct crystals. Boiling alcohol dissolves it in 
small quantity, and ether in much larger proportion. Cetine 
is saponified with great difficulty. By this process etlial and 
ethalic acid are obtained. The first is a crystallizable fat, 

369. Into what principles may wax be separated ? What is said of cerotic 
acid and myricine ? What are some of the sources of wax ? 

370. Whence is cetine obtained ? Mention some of its properties. What 
two products are obtained by its saponification ? What is said of ethal and 
ethalic acids ? Write the formula for cetine. 



ORGANIC CHEMISTRY. 


271 


whose melting point is nearly the same as that of the sper¬ 
maceti itself, but its solubility in alcohol is much greater. 
It is readily sublimed without decomposition. Ethalic acid 
resembles in many respects margaric acid. Cetine is com¬ 
posed of C 32 H 32 0 4 . 

371. Linseed oil is obtained from the seeds of common 
flax, which by great pressure yields about a their weight of 
oil. When it is obtained without the application of heat, it is 
most pure and of a pale yellow color. But the heat of steam 
is often applied at the same time with pressure, by which a 
greater quantity of oil is obtained, but this is less pure, of an 
amber color, and more liable to become rancid. The drying 
properties of linseed oil, which increase its value in painting, 
are greatly improved by boiling it for several hours with pro¬ 
toxide of lead {litharge), or peroxide of manganese. A little 
acetate of lead and sulphate of zinc are sometimes added. 
These substances combine with the gummy and mueilaginous 
matter of the oil, and precipitate them. When boiled for 
some time, if the oil is set on fire, and after half an hour ex¬ 
tinguished by placing a cover on the vessel, a viscid, tenacious 
oil is obtained, which, by the addition of lamp-black, forms 
printers’ ink. Linseed oil is also applied in making oil silk , 
which is silk cloth covered with several layers of .this oil. 
Oil-cloth is cotton cloth, prepared in a similar manner. White 
lead is generally made into paint with unboiled linseed oil, 
for boiling changes the color of the oil to a brownish red. 

372. Most of our vegetables contain oil. Fruits and seeds 
owe their fattening properties chiefly to the oil which is ac¬ 
cumulated in these parts of plants, especially in the seeds. 
Cattle are more rapidly fattened on oil cake (the refuse of 
linseed and other vegetable oil manufactories), than upon any 
other kind of v food. Indian corn contains 9 per cent of oil, 
oats 33, fine wheat flour I'4, bran from the same 4 , 65, rice 1, 
dry hay 3 to 4, wheat straw 3 2, oat straw 5*1, olive seeds 
54, linseed 22, white mustard 36, black mustard 18, sweet 
almonds 40 to 50, bitter almonds 28 to 46, cocoa-nuts 47, 
walnuts 40 to 70. 

373. Common oil contains a little mucilage, which it is 
extremely difficult to separate. This in burning, being a bad 
combustible, gathers around the wick and dims the light, 


371. Whence is linseed oil obtained ? How is it prepared for painting ? 

372. To what do frails and seeds chiefly owe their fattening properties? 
How much oil does fine wheat flour contain ?—wheat bran ?—wheat straw ?— 
sweet almond ? cocoa-nuts 1 —walnuts 1 

373. What impurity does common oil contain ? What effect has this upon 



272 


ELEMENTS OF CHEMISTRY. 


rendering it necessary to trim all kinds of lamps more or less 
frequently. The purpose served by the wick of a lamp is, 
not merely to draw up the fluid, but to raise the temperature 
of the oil to that of combustion. In the coarser oils or fats, 
this elevation of temperature is not sufficient to consume them 
entirely, and hence, as in tallow candles, the soot is deposited 
on the wick. Wax is a better combustible than tallow, and 
therefore it burns with a smaller wick, so that the little 
foreign matter which gathers on the wick weighs it down till 
it falls off together with the burnt part of the wick. 

Fat forms about ¥ V P art °f weight of a healthy animal. 
It varies in consistence, color, and smell, according to the 
animals from which it is obtained. It is generally found 
flaccid in the cetaceous tribes, soft, and rank-flavored in the 
carniverous, solid, and nearly scentless in the ruminants, 
usually white and copious in well-fed young animals, yellowish 
and more scanty in the old. 

SECT. I.-8. VOLATILE OILS. 

374. The odors of plants are due to the gradual evapora¬ 
tion of volatile oils, which are sometimes exceedingly diffused 
or diluted. Thus one hundred pounds of fresh roses or orange 
blossoms contain scarcely a quarter of an ounce of the fragrant 
oil, (our native roses furnish such small quantities of the oil 
that they are not worth distilling.) These oils sometimes per¬ 
vade the whole plant, and sometimes are confined to a single 
part. In some instances they are contained in distinct cel¬ 
lules, and in others formed upon the surface, as in many flowers, 
and exhaled as soon as they are formed. In cinnamon a vola¬ 
tile oil is found in the bark ; in camphor (one variety) in the 
root; in cedar in the wood; in mint, balm, &c., in the 
leaves ; in the carnation and rose in the flowers ; in oranges 
and lemons in the rind ; and finally in a great variety of 
seeds and fruits, as caraway, nutmeg, peach, strawberry, &c. 
Occasionally two or more are formed in different parts of the 
same plant. Thus the orange tree produces one volatile oil 
in its leaves, another in its flowers, and a third in the peel of 
its fruit. In a few instances, when existing in distinct cel- 


the combustion of the oil ? What is the purpose served by the wick of a 
lamp ? Why do not wax candles require to be trimmed ? What part of 
the weight of a healthy animal is fat? What is said of the different kinds of 
fat ? 

374. To what are the odors of plants owing? In what state are these 



ORGANIC CHEMISTRY. 


273 


lules, they may be obtained by pressure, as from the peel of the 
lemon and the orange, bat they are generally procured by 
distillation with water. 

Their boiling points are always higher than 212°, (usually 
from 316° to 320°,) and at this temperature they could not 
be distilled alone; but when the plants containing them are 
boiled with water, or pressed into cylinders or baskets, and 
hot steam passed through, the oils are carried over, and con¬ 
densed with the steam, forming a milky or turbid liquid, 
which gradually separates into oil and water. The water 
generally retains a portion of the oil, or the whole, if the 
quantity distilled is minute ; and, in this way, odoriferous 
waters are prepared. Plants which yield their oil easily are 
distilled with about six times their weight of water. Those 
from which the oil is extracted with difficulty are distilled 
with about ten times their weight of water. 

The volatile oils are almost all lighter than water, but a 
very few sink. A few of the volatile oils are solid at the 
ordinary temperature ; several become so at 32°, and many 
remain liquid considerably below this point. Heated in the 
air they take fire, and burn with a bright flame, attended 
with much smoke. Exposed at ordinary temperatures to the 
air, they absorb oxygen, assume a deeper color, and become 
thicker and less odorous. They are in this way ultimately 
converted into resin. This change takes place most rapidly 
under the influence of light. 

When pure the volatile oils are colorless, but they are 
usually yellowish, and sometimes brown, red, green, and even 
blue, from the presence of impurities. They have a strong 
odor, resembling that of the plants from which they were 
procured, though generally less agreeable. Their taste is 
pungent and burning. They mix in all proportions with fat 
oils, and dissolve freely in both ether and alcohol. From 
alcohol they are precipitated by the addition of water. They 
resist saponification completely. Any fixed oil with which 
they may be adulterated, may be detected by putting a drop 
on paper. The grease spot will disappear, if the volatile oil 
is pure, on warming the paper; but if fixed oil be present, 
the spot will remain. The volatile oils are very slightly 
soluble in water. 


volatile oils ? How are they generally procured ? Mention some of the prop¬ 
erties of volatile oils. Of what two principles do volatile oils consist' How 
may these be obtained ? 

12 * 





274 


ELEMENTS OF CHEMISTRY. 


Like the fixed oils, the volatile oils consist of distinct prin¬ 
ciples, which are congealed at different temperatures, and 
may be separated by compressing the frozen oil between the 
folds of bibulous paper. The solid matter remains upon the 
paper, and the fluid is absorbed by the paper, from which it 
may be separated by distillation with water. The solid por¬ 
tion is called stearopten , and the liquid elaoptene. The 
former often crystallizes out of certain volatile oils on stand¬ 
ing. It differs in almost every case. The volatile oils are 
exceedingly numerous ; some of the more common are arrang¬ 
ed beneath in groups according to their constitution : 


1. Volatile oils containing carbon and hydrogen : 


Turpentine, 

Lemon, 

Copaiva, 


Storax, 
Juniper, 
Cubebs, &c. 


2. Volatile oils containing carbon, hydrogen, and oxygen : 


Bitter Almonds, 
Cajeput, 

Rose, 

Lavender, 

Rosemary, 

Bergamot, 


Peppermint, 

Cinnamon, 

Pennyroyal, 

Valerian, 

Spearmint, 

Camphor, &c. 


3. Volatile oils containing sulphur : 

Black mustard, I Onions, 

Horse Radish, | Asafcetida, &c. 


375. Class I. Oil of turpentine , C 20 H 16 , may be taken 
as a representative of this class. It is obtained by distilling 
crude turpentine , which exudes from various pines and furs, 
or flows from wounds made for the purpose in the wood. 
This is now obtained chiefly from the wood of North Car¬ 
olina and Virginia. During the winter months excavations 
of the capacity of about three pints are made in the trunk 
of the tree, three or four inches from the ground. Into these 
the juice begins to flow about the middle of March, and 
continues to flow throughout the warm season, slowly at first, 
rapidly in the middle of summer, and more slowly again in 
the autumnal months. The liquid is removed from these ex- 


375. What do the oils of class first contain? Write the composition of the 
oil of turpentine. How is this oil obtained ? What is the solid product left 





ORGANIC CHEMISTRY. 


275 


cavations as they fill, and transferred into casks, where it 
gradually thickens, and ultimately acquires a soft solid con¬ 
sistence. Very large quantities are thus annually produced, 
sufficient not only to supply the whole consumption of this 
country, but also to furnish a valuable export. 

When this crude turpentine is distilled, the solid product 
left behind is common resin. When pure, oil of turpentine 
is perfectly limpid and colorless, of a strong, penetrating, pe¬ 
culiar odor, and a hot, pungent, bitterish taste. Its density 
in the liquid state is 0*865, and that of its vapor 4*764. It 
boils at 312°. Strong sulphuric acid chars and blackens this 
substance, and concentrated nitric acid and chlorine attack it 
with such violence, that inflammation sometimes ensues. 
With hydrochloric acid oil of turpentine forms a compound, 
which has been called artificial camphor, from its resem¬ 
blance to that substance in odor and appearance. It is pre¬ 
pared by passing hydrochloric acid gas into the pure oil, 
cooled by a freezing mixture. After some time a white 
crystalline substance separates, which may be purified by 
solution in alcohol. The dark acid liquid from which the 
precipitate is separated, contains a similar but fluid compound. 
Different specimens of the oil of turpentine yield very varia¬ 
ble quantities of these substances, which may perhaps arise 
from the existence of two very similar and isomeric oils in the 
ordinary article. 

Oil of turpentine is very largely used in painting, and as a 
solvent for resins in making varnishes. These are made by 
dissolving resin in one of the volatile oils, generally turpen¬ 
tine, or in alcohol. As the varnish dries, the turpentine 
evaporates, and the resin remains behind, and forms a hard 
coating, impervious to water. On account of its insolubility 
in water, resin may be precipitated from its alcoholic solutions 
by the addition of water, in the form of a dense white cloud. 

376. Class II. The essential oils of this class are very 
numerous. Two of the most important of these are the oil 
of bitter almonds, and that of cinnamon. 

Oil of bitter almonds is prepared in large quantities by 
distilling with water the paste of bitter almonds, from which 
the fixed oil has been expressed. It did not pre-exist in the 
almonds, being entirely wanting in the fat oil which is express- 


behind from the distillation of the crude turpentine ? 
properties of the oil of turpentinesome of its uses. 

376. What is said of the essential oils of class second l 
almonds prepared 1 State the properties of this oil. 


Mention some of the 

How is the oil of bitter 
Write its composition. 




276 


ELEMENTS OF CHEMISTRY. 


ed from the fruit, hut it is formed within the seed during the 
process of distillation. It may be purified by distillation with 
protochloride of iron and with hydrate of lime in excess. It 
is a colorless liquid of an agreeable odor, somewhat heavier 
than water. In water it is but slightly soluble, though very 
soluble in alcohol and ether. It boils at 356°. Pure bitter 
almond oil is probably not poisonous, but the common oil used 
to flavor puddings, custards, &c., often contains prussic acid 
(383), and is, therefore, highly dangerous. Its composition is 

c 14 h 6 o 2 . 

Oil of cinnam.on is prepared from cinnamon of the best 
quality. This is crushed, infused twelve hours in a saturated 
solution of common salt, and the whole subjected to a rapid 
distillation; water passes over milky with essential oil, which 
after a time separates. It is collected and left for a short 
time in contact with chloride of calcium, to remove com¬ 
pletely the water. This oil is heavier than water, and sinks 
to the bottom of the receiver in which the distilled products 
have been collected. Its composition is C ia H 8 0 2 . It is a 
fragrant and costly perfume. 

Camphor is a solid oil or fat of this class. Like the other 
volatile oils it is vaporizable without change at a moderate 
heat, nearly insoluble in water, and soluble with facility in 
spirit. It comes chiefly from Japan, where it is obtained 
from the wood of the laurus camphora , or camphor tree, by 
distillation with water in large iron pots, with earthen caps 
stuffed with straw. The camphor sublimes and concretes 
upon the straw. There is another kind of camphor which is 
called Borneo camphor, from the island whence it is ob¬ 
tained. 

Camphor possesses a very singular reaction with water and 
with the other volatile oils. If a small piece be placed on 
the surface of a basin of pure water, it will immediately begin 
to move round with great rapidity, but a single drop of any 
odoriferous liquid poured into the basin will instantly stop 
this motion. Camphor contains C 2 0 Hj 6 0 2 . Many volatile 
oils deposit, on long standing, solid compounds, (stearoptenes,) 
which are oalled camphors from their resemblance to this 
substance. 


How is the oil of cinnamon prepared ? State its properties, and write its 
formula. What is camphor 1 What are its properties ? Whence is cam¬ 
phor obtained ? Write its formula. What are deposited from many volatile 
oils on standing ? 



ORGANIC CHEMISTRY. 


277 


377. Class III. Oil of black mustard is obtained by dis¬ 
tillation from black mustard seed. The volatile oil does not 
pre-exist in the seed, but is formed during the distillation. 
When pure, the distilled oil is colorless, and has a most power¬ 
ful and suffocating smell, and a density of TO 15. It boils at 
289°. Water dissolves it in small quantity, and alcohol and 
ether very freely. The oil itself, at a higher temperature, 
dissolves both sulphur and phosphorus, and" deposits them in 
a crystalline form on cooling. It is oxydized with violence 
by nitric acid and by aqua-regia. Alkalies decompose it by 
the aid of heat. Mustard oil contains C 8 H 5 NS 2 . 

SECT. I. -9. RESINS AND BALSAMS.* 

378. Common resin or colophony furnishes, perhaps, the 
best example of this class. It contains two bodies having 
acid properties, called pinic and sylvic. Pure sylvic acid 
crystallizes in small, colorless, rhombic prisms, insoluble in 
water, soluble in strong and hot alcohol, in volatile oils, and 
in ether. It melts when heated, but cannot be distilled with¬ 
out decomposition. The properties of pinic acid are similar. 
Both these have the same composition, C 40 H 30 O 4 . 

White resin is the residue which remains from the evapora¬ 
tion of turpentine. In this process two different operations 
are going on at once ; a part of the volatile oil of the turpen¬ 
tine evaporates, and occasions the peculiar smell of the pine 
forests, but another part attracts oxygen from the air, and is 
converted into resin. 

Hesin soa|) (a combination of resin with potash or soda) 
is used in conjunction with alum for the sizing of paper. The 
soap is introduced first into the vat containing the paper pulp, 
succeeded by .a solution of alum. The resin combines with 
the alumina of the alum, forming an insoluble compound, 
which envelops each fibre of the paper. 

Rosin oil. An oil which is obtained by the distillation of 
common resin at a temperature of 550° to 6Q0° Fah. is thus 
named, and is used for lubricating machinery and a variety 
of other purposes. 

* Mixtures of resins and oils. By exposure to the air they become changed 
into resins by the evaporation of the oils. 


377. How is the oil of black mustard obtained ? What is said of this oil ? 
Write its formula. 

378. What two acids does common resin contain ? What is said of sylvic 
and pinic acids ? Write the composition of these acids. How is white resin 
obtained ? What is resin soap ? How is it used in sizing paper ? How is 
resin oil obtained ? For what is it used ? 



278 


ELEMENTS OF CHEMISTRY. 


379. Lac is a substance very similar to wax in the manner 
of its formation ; it is the product of an insect which collects 
its ingredients from flowers. It is formed into cells, fabricated 
with as much skill as those of the honey-comb, but differently 
arranged. It is a very valuable resin, much harder than 
colophony, and easily soluble in alcohol. Lac is used in 
varnishes, and in the manufacture of hats, and very largely 
in the preparation of sealing-wax, of which it forms the 
chief ingredient. Crude lac contains a red dye, which is 
partly soluble in water. A hot solution of borax dissolves 
lac in considerable quantity. By rubbing India ink in this 
solution, a label ink may be formed, which will be unaffected 
by acid vapors, and when once dry, becomes nearly insoluble 
in water. 

380. Caoutchouc , India-rubber , is a milk-white juice 
which exudes from several large trees of South America and 
the East Indies. 


The ficus elastica, or the caoutchouc tree of Assam, is larger than 
any other tree in the extensive forest where it abounds, and may be 
distinguished from the other trees at a distance of several miles, by its 
dense, huge, and lofty crown of foliage. The main trunk of one, which 
was carefully measured, was found to have a circumference of no less 
than 74 feet, and, as this tree is one of the banyan family, the girth of 
the main trunk, with the supports immediately around it, was 120 feet. 
The area covered by the expanded branches had a circumference of 
610 feet. The height of the central tree was 100 feet. Of these trees 
it is estimated that there are no less than 43,240 within a length of 30 
miles, and breadth of 8 miles of forest, near Ferozepoor in Assam. 
Though the geographical range of this tree in Assam is confined to a 
few degrees of latitude, it occurs on the slopes of hills, up to an eleva¬ 
tion of probably 22,600 feet. Incisions are made in the tree through the 
bark to the wood, all around the trunk, and also the large branches up 
to the very top of the tree, the quantity which exudes increasing with 
the height of the incision. The juice is better when drawn from old 
than from young trees, and richer in the cold season than in the hot. 
It may be safely extracted once every fortnight; but the bleeding is 
generally confined to the cold months, in order not to obstruct the 
vigorous vegetation of the tree in the hot months. About 46 lbs., or 
somewhat more, is reckoned as the average product of each bleeding of 
one tree, or 1,978,000 lbs. for 43,000 trees. This juice is composed of 
about half caoutchouc and half water. As it trickles from the incis¬ 
ions, it is collected in clay moulds of various forms. A layer adheres 
to the clay, and dries on it, and several layers are successively added. 
When sufficient thickness has been obtained, the mould is broken up, 
and shaken out of the solid caoutchouc. In this country and in England 


379 . What is said of lac ? Mention some of its uses. 

380 . Whence is caoutchouc obtained? What is said of the caoutchouc 
tree ? How is the juice obtained ? How is its dark color produced ? What 



ORGANIC CHEMISTRY. 


279 


it is cut up, and manufactured into a great variety of articles. Some¬ 
times its dark color is produced by smoke, but mere exposure to the 
air for a few weeks will produce this effect to a considerable extent. It 
is softened but not dissolved in boiling water, and is also insoluble in 
alcohol. In pure ether, rectified native naphtha, and petroleum (coal 
tar), it dissolves, and is left unchanged on the evaporation of the solvent. 
Hence, in makiog India rubber cloth, two surfaces of cloth are cemented 
together with a varnish made of caoutchouc dissolved in one of these 
liquids, and this forms a compound impervious to air and water. The 
caoutchouc is also sometimes dissolved in oil of turpentine, which forms 
a viscid adhesive mass, drying but imperfectly. At a temperature a 
little above the boiling-point of water, caoutchouc melts, but never 
afterwards returns to the firmer elastic state. Few chemical agents 
affect this substance; hence its great use in the practical operations of 
chemistry. Bags of it soaked in ether until they become gelatinous, 
may be distended by blowing to a very great size, and thus become use¬ 
ful for a great variety of purposes. When caoutchouc thread is used in 
the loom, it is necessary that its elasticity should be removed until it is 
woven, and then restored. The thread is rendered inelastic and finer 
by the same process. It is first soaked in a dub of cold water, and 
then softened in hot water, and finally wound upon a reel turned 
quickly, while the operator stretches the caoutchouc with his hand, so 
that its length is increased 8 or 10 times. The reels, when thus filled, 
are placed during some days in a cold apartment, where the thread 
becomes firm. This process renders the thread inelastic, but their 
elasticity when woven is easily restored by passing a hot smoothing- 
iron over the tissue laid upon a table covered with blanket stuff. 
Ropes are sometimes made of the strongest of these threads braided 
with hemp. These ropes possess, after their elasticity is restored, a 
strength double that of cordage of like diameter. 

For the method of uniting sheet India-rubber, see Appendix, under 
the head of “ chemical processes.” 

Threads of caoutchouc are readily united by paring the ends obliquely 
with scissors, and then pressing them together, taking care to admit no 
grease or moisture within the line of junction. 

Vulcanization of Caoutchouc. When a sheet of caoutchouc is im. 
mersed for some time in melted sulphur at a temperature of 275° to 
320° Fahr., it undergoes a remarkable change of properties. The same 
object may be accomplished by grinding the rubber and sulphur to¬ 
gether, and then exposing the mixture to heat. As thus prepared, 
caoutchouc is no longer affected by the alternations of heat and cold. 
It is also rendered permanently elastic and insoluble in the ordinary 
solvents of caoutchouc. A great number of applications of this vulcan¬ 
ized rubber have already been made, and this number is daily in¬ 
creasing. 

381. Gutta-percha is produced from several trees in the East Indies, 
especially from the tree called percha , found in the island of Singapore, 
and in the countries adjacent. This tree is of considerable magnitude, 
with a trunk commonly three feet, and sometimes as much as six feet 
in diameter. The natives procure the gutta-percha by cutting down 


are some of its properties and uses 1 How is caoutchouc manufactured into 
thread and cloth ? Describe the vulcanization of caoutchouc. 

381. Whence is gutta-percha obtained ? Mention some of its properties 




280 ELEMENTS OF CHEMISTRY. 

the tree, stripping off the bark, and then collecting this substance, which 
is found interposed, in the concrete state, between the wood and the 
bark. Twenty or thirty pounds are thus collected from each tree. It 
has the advantage over caoutchouc, that, though quite hard when cold, 
it becomes soft and plastic by moderate heating. 

Gutta-percha has a dull white or whitish color, and a feeble odor. It 
is tasteless, hard, almost horny at ordinary temperatures, somewhat 
flexible in thin pieces, and very tenacious. At 110° no effect is pro¬ 
duced upon it, except that it receives the impression of the nail more 
readily. At about 120it becomes softer and more flexible; at 150° 
or 160° it is soft, very plastic, and capable of being welded and moulded 
into any form. In the softened state, which may be produced by hot 
water or by dry heat, it is readily cut with a knife, though with some 
difficulty when cold. Exposed to a heat of 330°, it loses a portion of 
water, and, on hardening, becomes translucent and gray; but it re¬ 
covers its original properties if immersed in water. Heated in an open 
vessel it melts, foams up, and takes fire, burning with a brilliant flame 
and with smoke. 

By different processes gutta-percha is made elastic like caoutchouc, 
hard like marble, and fit to spread on cloth, thick or thin. Gutta¬ 
percha may be vulcanized in the same manner as caoutchouc, and by this 
process undergoes a similar change of properties. A table-slab has 
been made of it, and long used without injury, having the external 
qualities of polished marble. Utensils of various kinds, medallic and 
other ornamental impressions, casts, sheets, bands, cords, (which do not 
shrink like hempen cords), tubes, (which do not stretch out like Indian- 
rubber,) &c., may be made of it with great facility. It is so tenacious, 
that a cord one-eighth of an inch in thickness easily raised a weight of 
42 pounds, and only broke when a weight of 50 pounds was attached 
to it. It has also been introduced into surgery, in order to preserve 
limbs and joints in fixed positions. For this purpose gutta-percha bands 
are prepared, two or three inches broad, and one-twelfth of an inch 
thick, which are first softened in warm water, and then applied to the 
limb. These bands soon harden, and form a firm case for a limb. If a 
solution of gutta-percha in bisulphuret of carbon is spread over a 
wound, the liquid will soon evaporate, and the gutta-percha hardening 
will form a protection to the wounded part. One of the most important 
of the uses of gutta-percha is in covering telegraph wire, especially 
where this wire is conveyed under water. Its composition and that of 
caoutchouc are nearly alike: 

Carbon. Hydrogen. Specific gravity. 

Gutta-percha, 87*8, 12-2, 0-9791. 

Caoutchouc, 87'2, 12-8, 0-9355. 


and uses. Write the composition of gutta-percha and caoutchouc. 



ORGANIC CHEMISTRY. 


281 


SECTION II.—THE AZOTIZED PRINCIPLES. 

SECT. II.-1. CYANOGEN, FULMINIC ACID. 

382. Cyanogen , C 2 N, is prepared by heating cyanide of 
mercury (385.) to redness. This salt is decomposed into 
metallic mercury, and a colorless, inflammable gas, called 
cyanogen. It has a pungent and peculiar odor, and burns 
with a beautiful purple, or peach-blossom flame. At the 
temperature of 45°, by a pressure of 36 atmospheres, it con¬ 
denses to a thin, colorless, transparent liquid. Water absorbs 
4 or 5 times its volume of this gas, and alcohol a much 
larger quantity, but the compound thus formed is rapidly de¬ 
composed. Its specific gravity is 1*806, its symbol Cy. 

Cyanogen, though a compound, like the organic radicals, 
(p. 229) unites with the elements exactly in the same manner 
as though it were an element. Though not a simple body 
in its composition, yet, as it is simple in all its relations, it 
may be considered as coming under the third law of affinity, 
p. 61, “ that simple bodies unite only with simple, and com¬ 
pound with compound bodies.” In its relations to other 
bodies, it is so closely related to the elements chlorine, iodine, 
bromine and fluorine, that it is sometimes classed with these 
bodies. Like these bodies it forms with hydrogen an acid, 
hydrocyanic or prussic acid , and like them also it unites 
with the metals forming protocyanides and percyanides. 

383. Hydrocyanic, or prussic acid , HCy, or H-fC 2 N. 
Anhydrous prussic acid is a thin, colorless, and very volatile 
liquid, which exhales a very strong odor of peach-blossoms. 
It is one of the most formidable poisons known, and even 
when largely diluted with water, its effects on the animal 
system are exceedingly energetic. It is employed in medicine, 
but so diluted with water, that 100 grains of the strongest 
mixture do not contain more than 3 grains of the pure acid, 
and yet a single drop of this diluted acid is a dose, and must 
be administered with caution. Its odor is so strong as to 
produce immediate head-ache, often fainting. Its vapor can¬ 
not be inhaled without the greatest danger. The best anti- 


382. Write the symbol of cyanogen. How much carbon do 26 parts of 
cyanogen contain V How is this gas prepared ? Mention some of its proper¬ 
ties. Is cyanogen an exception to the law that simple bodies unite with sim¬ 
ple bodies, and compound with compound bodies? To what elements is it 
closely related? 

383. Write the symbol of prussic acid. How much hydrogen do 27 parts 
of prussic acid contain ?—how much carbon ?—how much nitrogen ? how 



282 


ELEMENTS OF CHEMISTEY. 


dote is a solution of mixed sulphate of protoxide and peroxide 
of iron, followed by some carbonate of potash.' By this means 
the acid is converted into insoluble Prussian blue. Ammonia 
is also used, but the poison is often fatal before any antidote 
can be obtained. 

Pure hydrocyanic acid volatilizes so rapidly, that a drop of 
it held on the end of a glass rod, becomes solid by its own 
evaporation. Though usually a product of art, this acid ex¬ 
ists in, or is formed during the distillation of the cherry 
laurel, bitter almonds, bird cherry, peach, and some other 
plants. It may be detected by its smell, and by its yielding 
a precipitate of Prussian blue, when acted on in solution suc¬ 
cessively by sulphate of iron, potash, and an excess of hy¬ 
drochloric acid. If the liquid in which the poison is supposed 
to exist be acidulated with sulphuric acid and distilled, the 
prussic acid will be found in the first portions which come 
over. 

384. Cyanide of potassium, KCy, forms colorless, cubic or 
octahedral, anhydrous crystals, deliquescent in the air, and 
exeedingly soluble in water. Its solution has an alkaline 
reaction. All acids decompose this salt, even the carbonic 
acid of the atmosphere, to which is owing the smell of hydro¬ 
cyanic acid, which it emits when exposed to the air. Cyanide 
of potassium is exceedingly poisonous, acting precisely like 
prussic acid. The tenth of a grain of the salt killed a 
small bird in the space of a minute ; a solution of five 
grains destroyed a large dog in a quarter of an hour. As 
a medicine, it is considered applicable to all cases in which 
hydrocyanic acid has been found useful. Cyanide of potass¬ 
ium has highly important uses in chemical analysis. 

385. Cyanide of mercury , HgCy. One of the most re¬ 
markable properties of cyanogen is its powerful attraction 
for certain of the less oxidable metals, as silver, and more 
particularly mercury and palladium. Dilute hydrocyanic acid 
dissolves finely-powdered red oxide of mercury with the ut¬ 
most ease, the liquid loses all odor, and yields on evaporation 
crystals of cyanide of mercury. Cyanide of potassium is also 
decomposed by red oxide of mercury, the cyanogen passes to 


much cyanogen? Of what strength is the acid employed in medicines? 
What is the best antidote to its poisonous effects ? Where does prussic acid 
occur naturally ? How may it be detected ? 

384. Write the symbol of cyanide of potassium. Mention some of its pro¬ 
perties ;—its uses. 

385. Write the symbol of cyanide of mercury. Mention some of its pro¬ 
perties. 



ORGANIC CHEMISTRY. 


283 


the mercury forming cyanide of mercury, and the oxide of 
potassium or potash is left in the state of a hydrate. Cyanide 
of mercury forms white, translucent prisms, much resembling 
those of corrosive sublimate, which are soluble in 8 parts of 
cold water, and in a much smaller quantity of hot water. 
They are also soluble in alcohol. The solution has a dis¬ 
agreeable, metallic taste, and is very poisonous. 

386. Cyanic acid, CyO, HO, is formed when dry cynaide 
of potassium is heated in the air, or when a reducible metallic 
oxide is added to it, when in the fused state. Oxygen is 
taken up, and cyanate of potash, KO, CyO, is formed. When 
a strong acid is added to this salt, the cyanic acid is set 
free, but is immediately decomposed, producing ammonia and 
carbonic acid. 

Cyanate of ammonia, NH 4 0, CyO, is remarkable chiefly 
for the transformation which it undergoes when its solution is 
evaporated, being changed into urea, C 2 N 2 H 4 0 2 , by taking 
up the elements of water. This substance, which is secreted 
abundantly in the animal economy, was the first example of 
an organic product formed artificially. It belongs to the 
so-called organic bases, crystallizing in square prisms, and 
combining with nitric, oxalic and other acids. 

387. Ferrocyanide of potassium, 2K, Cfy-f-3HO. The 
symbol Cfy, is that of a body not yet described, called ferro- 
cyanogen, C 6 N 3 , Fe. When a solution of cyanide of potass¬ 
ium is digested with iron filings at a gentle heat in an open 
vessel, oxygen is absorbed from the air, and the iron dissolves 
quietly and disappears. A highly alkaline, yellow liquid is 
obtained, which, on evaporation, leaves lemon-yellow crystals, 
containing potassium in combination with a new salt-radical, 
which is composed of the metal iron (Latin ferrum ) and 
the elements of cyanogen, and hence called ferro-cyanogen. 

Ferrocyanide of potassium is a chemical reagent of great 
value. When mixed in solution with neutral or slightly 
acid salts of the metals, it gives rise to precipitates which 
very frequently present highly characteristic colors. Some 
of these are given in the following table : 


386. How is cyanic acid formed ? What takes place when strong acid is 
added to cyanate of potash? What is said of cyanate of ammonia?—of 
urea ? 

387. Write the composition of ferrocyanide of potassium. In this formula 
what does Cfy denote? How much potassium is contained in 211 parts of 
ferrocyanide of potassium ?—how much carbon ?—how much nitrogen ?—how 
much iron ?—how much water ? How is Prussian blue prepared ? 



284 


ELEMENTS OF CHEMISTRY. 


Precipitate. 

white. 

apple-green. 

grass-green. 

reddish-brown. 

blood-red. 


Tin, Zinc, Manganeset Antimony. V White. 

Cadmium, Bismuth, Cerium, ) 

Ferrocyanide of iron. Prussian blue, Fe 4 Cfy 3 , is a well- 
known pigment, and is formed by mixing solutions of ferro¬ 
cyanide of potassium and of a persalt of iron. 

388. Ferricyanide of potassium , 3 K-fOfdy, is supposed 
to be composed of 3 eq. of potassium, and one of new salt- 
radical, called ferri, or ferridcyanogen, whose symbol is Cfdy, 
and which has never been isolated. It forms regular, pris¬ 
matic, and sometimes tabular crystals, of a beautiful ruby-red 
tint, permanent in the air, and soluble in 4 parts of cold 
water. The crystals burn when introduced into the flame of 
a candle, and emit sparks. Its solution with peroxide of iron 
yields a deep red color. 

389. Sulphocyanide of potassium , KCsy. The elements 
of cyanogen combine with sulphur, forming a well-defined 
salt-radical, called sulphocyanogen , which contains C 2 IsTS 2 , 
and is expressed by the symbol Csy. Its compound with 
potassium crystallizes in long, slender, colorless prisms, or 
plates, which are anhydrous. This salt is the most delicate 
test known for iron when in the state of peroxide. 

390. Fulminic acid , Cy 2 0 2 + 2HO, is known only in com¬ 
bination. Some of its salts are characterized by the violence 
with which they detonate from a very slight disturbance. 

Fidminate of silver, 2AgO, C 4 N 2 0 2 , is prepared by dis¬ 
solving 40 or 50 grs. of silver, which need not be pure, in a 
half oz., by measure, of warm nitric acid (sp. gr. T37). To 
the solution, while still hot, add two measured ounces of al¬ 
cohol, and apply heat until reaction commences. The ful¬ 
minate of silver slowly separates from the hot liquid in small 
crystalline plates, which are washed with a little cold water, 
* Changing to blue. t Becoming rose. 


Metal. 

Iron, protoxide, 

“ (peroxide), 
Copper, protoxide, 
“ ’ deutoxide, 
Platinum, 
Palladium, 


Precipitate.' 
white* 
deep-blue, 
white. 

deep-brown. 

yellow. 

olive. 


Metal. 

Silver. 

Nickel, 

Cobalt, 

Titanium, 

Uranium, 


Gold, Mercury (deutoxide), Lead, } 


388. Write the composition of ferricyanide of potassium. In the formula 
what does Cfdy denote ? What are the properties of this substance ? 

389. Write and explain the formula for sulphocyanide of potassium. How 
much potassium in contained in 97 parts of sulphocyanide of potassium?—how 
much carbon ?—how much nitrogen ?—how much sulphur ? 

390. Write and explain the composition of fulminic acidfulminate of 
silver. How is this salt prepared ? What are its properties ? Write and 




ORGANIC CHEMISTRY. 


285 


distributed upon separate pieces of filter paper in portions not 
exceeding 1 a grain or two each, and left to dry in a warm 
place. When dry, the papers are folded up and preserved in 
a box or bottle. This is the only safe method of keeping the 
salt. Fulminate of silver is soluble in 36 parts of boiling 
water, but the greater part crystallizes out on cooling. It 
explodes with wonderful violence with concentrated sulphuric 
acid, and when strongly heated, or when rubbed or struck 
with a hard body. The metal is reduced, and a large amount 
of gaseous matter liberated. Notwithstanding its explosive 
energy when alone, if cautiously mixed with oxide of copper, 
it may be burned in a tube with as much facility as any or¬ 
ganic substance. 

Fulminate of mercury , 2HgO, C 4 N 2 0 2 , is prepared by a 
process very similar to that by which the silver salt is obtain¬ 
ed. One part of mercury is dissolved in 12 parts of nitric 
acid, and the solution mixed with an equal quantity of al¬ 
cohol. Gentle heat is applied, and, if the reaction becomes too 
violent, it is moderated by the addition from time to time of 
more spirit. The fulminate of mercury separates from the 
hot liquid, and after cooling may be purified from an admix¬ 
ture of reduced metal by solution in boiling water and re¬ 
crystallization. It much resembled the silver salt in appear¬ 
ance and properties. It explodes violently by friction or per¬ 
cussion, but merely burns with a sudden and almost noiseless 
flash when kindled in the open air. If a train of common 
powder is placed alongside of another train of fulminating 
powder, (either fulminate of silver, or fulminate of mercury,) 
and fire be applied, the explosion of the fulminating powder 
will be so sudden as to disperse the other without burning. 
If the train of common powder extend beyond that of the other 
kind, and fire is applied to this extremity of the common 
powder, it will burn till the flame reaches the fulminate, 
when the remainder will be dispersed without burning. It is 
manufactured on a large scale for the purpose of charging 
jpercussion-caps. One of these contains only one-third of a 
grain of fulminate of mercury ; sulphur and chlorate of pot¬ 
ash are added (202.), and the powder pressed into the cap, 
secured by a drop of varnish. 


explain the formula for fulminate of mercury. State the process by which it 
is prepared, and mention its properties. What are some of its uses ? De¬ 
scribe the experiment with a train of common powder. 



286 


ELEMENTS OF CHEMISTRY. 


SECTION II. -2. VEGETABLE ALKALIES. 

391. The vegetable alkalies, or alkaloids, constitute an ex¬ 
tensive class of bodies (several hundred have been already 
discovered), which are; for the most part, the active medicinal 
agents of the plants in which they occur. They are generally 
sparingly soluble in water, but more soluble in boiling alcohol, 
from which they crystallize in a very beautiful manner on 
cooling. The taste of these substances is intensely bitter, and 
their action on the animal economy exceedingly energetic. 
They all contain a considerable quantity of nitrogen, and are 
very complicated in their constitution, having high combining 
numbers. Morphia, narcotine, cinchonia, quinine, strychnia, 
and brucia, belong to this very numerous class of bodies. 

392. Morphia , or morphine , C 35 H 20 !N’O 6 , is the chief 

active principle of opium, and the most characteristic type of 
this group of bodies. When crystallized from alcohol, mor¬ 
phia forms small but very brilliant, prismatic crystals, which 
are transparent and colorless. Opium sometimes contains 
10 parts in 100 of morphine. At least 1,000 parts of water 
are required for its solution, which tastes slightly bitter, and 
has an alkaline reaction. These effects are much more evi¬ 
dent in the alcoholic solution. It dissolves in about 30 parts 
of boiling alcohol, but the greater part crystallizes from the 
solution upon cooling. In dilute acids it dissolves with great 
facility, and it is also dissolved by excess of caustic potash or 
soda, but scarcely by excess of ammonia. In powder, mor¬ 
phia strikes a deep bluish color, with a neutral persalt of 
iron, decomposes iodic acid with liberation of iodine (by this 
reaction P art °f morphine can be detected in solution), 

and forms a deep yellow or red compound with nitric acid. 

393. Narcotine , C 46 H 25 N0 14 , is also obtained from 
opium. Though very poisonous to some animals (2 scruples 
speedily killed a dog; a smaller dose brings on stupor, from 
which the animal never recovers), yet it is doubtful whether 
narcotine, if free from morphine, has any action on the human 
system. On the other hand, some of the salts of morphine, 
which are deadly poisons to man, have been given in con¬ 
siderable doses to a number of animals, even to birds and 
smaller quadrupeds, without destroying life. 


391. What is said of the vegetable alkalies ? 

392. Write the composition of morphia. Where is this substance found ? 
Mention some of its properties. 

393. What is said of narcotine ? 




ORGANIC CHEMISTRY. 


287 


394. Cinchonia , C 20 H 12 NO, and quina , C ?0 H 12 NO 2 , 
are contained in Peruvian bark, and give to it its valuable 
properties. They are associated in the bark with sulphuric 
acid, and a special acid not found elsewhere, called the kinic. 
Cinchonia is contained in the largest quantity in the pale 
bark, quina in the yellow, and both are contained in the red 
bark. 

Pure cinchonia crystallizes in small but beautifully brilliant, 
transparent, four-sided prisms. It is but little soluble in 
water (in 2,500 parts). It is very soluble in boiling alcohol, 
which deposits a portion in the crystalline state upon cooling. 
Its alkaline character is very decided, as it neutralizes the 
strongest acids, forming with them saline compounds. Its 
salts are intensely bitter. 

395. Quina , or quinine , much resembles cinchonia. It 
does not crystallize so well, and is much more soluble in 
water. By cautious management it may be crystallized in 
pearly, silky needles. It is fusible like the resins, and be¬ 
comes brittle on cooling. Its taste is intensely bitter. 

Sulphate of quinine is manufactured on a large scale for 
medicinal uses. It crystallizes in fine, silky, slightly flexible 
needles, interlaced among each other, or grouped in small 
star-like tufts. Its taste is intensely bitter. It is very slightly 
soluble in water, and the solution is neutral. Its solubility is 
much increased by the addition of a little sulphuric acid. 
This salt has the same action on the system as Peruvian 
bark, without being so apt to produce nausea and other bad 
effects. It may, therefore, be substituted for that remedy in 
most diseases to which the latter is applicable. 

396. Strychnia , C 4 4 H 2 4 IST 2 0 8 , is contained in nux vomica , 
and several other plants. Under favorable circumstances, it 
crystallizes in small, but exceedingly brilliant, octahedral 
crystals, which are transparent and colorless. Rapidly crys¬ 
tallized, it is in the form of a white powder. It is but 
slightly soluble in water (in 7,000 parts), and so intensily bit¬ 
ter, that it communicates a characteristic taste to 600,000 
parts of water. It dissolves in hot and somewhat dilute 
spirit, and in volatile oils. It is one of the most violent 
poisons known. It is sometimes used as a medicine, but un- 


394. Write the composition of cinchonia. Whence is this substance ob¬ 
tained ? What are its properties ? 

395 . What is said of quina ?—sulphate of quinine ? 

396. Write the composition of strychnia. Whence is this substance ob¬ 
tained ? W hat are its properties ? 



288 


ELEMENTS OF CHEMISTRY. 


less it is employed in exceedingly small quantities, it acts 
with fearful energy, causing lock-jaw immediately, and death 
in a very short time. Half a grain blown into the throat of 
a rabbit proved fatal in five minutes. The salts of strychnia, 
which are more soluble than strychnia, are also more 
poisonous. 

397. Caffeine , theine, Cj 6 H T 0 N 4 O 4 , is contained in coffee 
and tea, and in several other plants which are employed by 
different nations to prepare a stimulating beverage. 

The caffoea Arabica, from which coffee is obtained, is a native of 
Upper Ethiopia and Arabia Felix. There are several other species of 
the same genus, but this is the only one which is cultivated. The most 
extensive culture of coffee is still in Arabia Felix. It is generally 
grown about half way up the slopes of high mountains, where the air is 
more mild than in the plains; or, if grown in the latter, it is beneath the 
shade of large trees, which prevents its fruit from withering before its 
maturity. The leaves of this tree resemble those of the common laurel, 
although not so dry and thick as the latter commonly are. Small 
groups of white sweet-scented flowers issue from the angles of the leaf¬ 
stalks, which suddenly appear throughout the plantation, and very soon 
fade, and are then replaced by a fruit much like a cherry, which, when 
ripe, is of a dark-red color, and contains a yellow fluid, and seeds or ber¬ 
ries. These seeds constitute the coffee of commerce. 100 parts of dif¬ 
ferent varieties of coffee contained of caffeine as follows : 

Martinique coffee, 64 Mocha coffee, 4‘0. 

Alexandria “ 4 - 4 Cayenne “ 3*8. 

Java “ 4*4 St. Domingo “ 3’2. 

The tea-plant is much smaller than that which produces coffee. Its 
leaves and blossoms resemble those of the common hawthorn. It grows 
either in low or elevated situations, but thrives best, and furnishes 
leaves of the finest quality, when produced in light, stony ground. Old 
teas are less energetic than those recently imported. Before tea- 
leaves can be used with safety, they must be subjected to a con¬ 
siderable heat, and kept in a dry state for at least twelve months. 
It is said that fresh leaves have produced dangerous effects. 

398. Nicotine, the alkaloid of tobacco, is one of the most 
virulent poisons. A single drop was sufficient to destroy a 
dog; ]■ of a drop to kill a rabbit. The liquid which con¬ 
denses in a smoking-pipe contains a large proportion of nico¬ 
tine. In the fermentation which tobacco always undergoes 
in its preparation, it loses f of its nicotine, without which 
loss few persons could use it. Its vapor is so irritating, that 
one single drop evaporated in a room renders the air almost 


397. Write the composition of caffeine. What is said of this alkaloid ? 

398. What is the source of nicotine I Mention some of its properties. 



ORGANIC CHEMISTRY. 


289 


irrespirable. Its formula is C 2 0 H M N 2 . The following table 
exhibits the quantity of nicotine from 100 parts of various 
kinds of tobacco dried at 212° : 

Maryland, 2-29. Cigars of first quality, 2-00. 

Virginia, 6-87. Inferior cigars, 7*96. 

Kentucky, 6-09. Snuff, 2-04. 

The fine tobacco employed for smoking contains much less 
nicotine than the coarser kinds. 

399. Artificial alkaloids ,. Within the last few years many 
important discoveries have been made in the formation of 
artificial bases, similar to the natural ones just described. 
These are obtained by the action of ammonia on organic sub¬ 
stances, by the destructive distillation of animal and vegeta¬ 
ble matters containing nitrogen, and in a variety of other 
ways. Among the most remarkable of these bases are the 
so-called compound ammonias , which are formed from am¬ 
monia by the replacement of one or more equivalents of hy¬ 
drogen by the compound radicals, ethyle, methyle, &c. 

Metkylamine, C 2 H 5 N. is formed by the action of potash 
on -the cyanic ether of wood-spirit. It is a gas of the spec, 
grav. 1.075, condensing to a liquid at a little below 32°, and 
has an odor very closely resembling that of ammonia, to 
which it is quite similar in all its properties. Ethylamine , 
C 4 H 7 N, is similar in its mode of production and properties 
to methylamine. These bases are found associated with am¬ 
monia in the oil of coal tar and other products of the dis¬ 
tillation of animal matters, and are probably formed, also, 
during their putrefaction. 

SECTION II. -3. ORGANIC COLORING PRINCIPLES. 

400. Few plants contain colors that are permanent when 
exposed to the air and sun. Most of the beautiful tints of 
flowers fade and disappear soon after the flowers are gather¬ 
ed, and the coloring matter is so minute, that it is impossible 
to extract it by pressure, or so evanescent that it cannot be 
long preserved. We find, however, in a few instances, some¬ 
times in the roots of the wood, and sometimes in the leaves, 
a coloring juice of greater permanence and density, which 

399. How is methylamine obtained ? What are its properties ? Where 
are these bases found 1 

400. Why cannot most of the vegetable colors be preserved How are 
those coloring matters which are more permanent usually extracted ? What 

13 





290 


ELEMENTS OF CHEMISTRY. 


may be extracted and employed for coloring other substances. 
This is extracted generally by water, but sometimes by al¬ 
cohol or other liquids. Most of the organic coloring principles 
are of vegetable origin, but cochineal and kermes and some 
of the animal fluids, as the blood and the bile, are strongly 
colored. The art of dyeing is founded upon an affinity, or 
attraction, existing between the coloring matter of the dye 
and the fibre of the cloth. In woollen and silk this affinity is 
usually very considerable, and to such tissues a permanent 
stain is communicated, but with cotton or flax it is much 
weaker. To render the color permanent in these cases, a 
third substance is employed, which possesses a high degree of 
affinity, both for the fibre of the cloth and the coloring matter. 
Alumina, peroxide of iron, and oxide of tin, are usually em¬ 
ployed for this purpose. With these substances the cloth is 
first impregnated, and afterwards colored with the dye. An 
insoluble substance is thus formed in the fibre of the cloth. 
The same substance may be formed by precipitating some color¬ 
ed infusion, as an infusion of logwood, containing a little alkali, 
by alum. The precipitate consists of alumina, in combination 
with the coloring matter. This combination is called a lake. 
When this compound is formed within the fibre of the cloth, a 
permanent dye is effected. Alumina, peroxide of iron, and other 
bodies which are employed to render colors permanent, are 
called mordants (245.) Oxide of iron gives rise to 'dull, 
heavy colors; alumina and oxide of tin, especially the latter, 
to brilliant ones. By applying the mordant 'partially to cloth, 
by a wooden block or otherwise, a pattern may be produced, 
for the color will be permanent only where the mordant is 
applied, and may be washed out of the other part. 

401. Chlorophyll. This is the most abundant of all the 
vegetable coloring matters, being found in the leaves, stalks, 
unripe fruit, and juice of all except the lowest classes of 
plants, such as algse, mosses, &c. It is extracted by ether, 
and purified by the successive action of alcohol and hydro¬ 
chloric acid. From the acid solvent it is precipitated by water. 
It forms a dark green mass, the powder of which is grass- 
green. The yellow and red tints of leaves in autumn are 
undoubtedly modifications of chlorophyll, although opposite 


coloring- matters are of animal origin ? Upon what is the art of dyeing- founded ? - 
What is the strength of this attraction in wool and silk ?—in cotton and flax ? 
How do mordants render colors permanent ? 

401. Where is chlorophyll found ? How is it extracted? What is said of 
the colors of leaves in autumn l— of the colors of fruits % 



ORGANIC CHEMISTRY. 


291 


views are held in regard to the nature of this modification. 
If a red leaf is macerated in potash solution, it becomes 
green, In acid solutions it becomes yellow. Green leaves 
are also turned yellow by acids. The colors of fruits are prob¬ 
ably owing to the same modification of chlorophyll as that 
of leaves in fall. Plants which bear red or blue fruits have 
red leaves in fall, while those which bear white or light-color¬ 
ed fruits generally turn yellow in autumn. Young leaves 
have a much lighter color *than those which are older, be¬ 
cause the quantity of chlorophyll increases “with the age of 
the leaves. . 

402. Indigo is rendered, by the addition of mordants, the 
most important of the vegetable colors. Without mordants it 
gives a color that is soon lost, and hence, before the use of 
these substances was known, in the reign of Q,ueen Elizabeth, 
indigo and logwood were forbidden to be used as dyes. By 
an act of parliament, the dye-houses were searched, and these 
two substances when found were burnt. This act remained 
in full force till the time of Charles II., or for a century. 

Indigo is the product of several plants of the genus indigo- 
fera, which grow principally in warm climates. When the 
leaves of these plants are placed in a vessel of water, and 
allowed to ferment, a yellow substance is dissolved out, which, 
by contact of air, becomes deep blue and insoluble, and finally 
precipitates. This, when washed and carefully dried, forms 
.the indigo of commerce. It is not contained in the plant, but 
is produced by the oxidation of some substances there present. 
The best indigo is so light as to swim upon water ; its powder 
has an intensely deep blue tint. It may be freed from its 
impurities, which usually constitute at least half of its weight, 
by being powdered and boiled in dilute acid, in alkali, and 
afterwards in alcohol. 

Pure indigo is quite insoluble in water, alcohol, oils, dilute 
acids and alkalies. It dissolves in about 15 parts of concen¬ 
trated sulphuric acid, forming a deep blue, pasty mass, en¬ 
tirely soluble in water, and often used in dyeing. In contact 
with deoxidizing agents, and with an alkali, indigo suffers 
a remarkable change ; it becomes soluble and nearly color¬ 
less, perhaps returning to the same state in which it existed 
in the plant. On this principle the dyer prepares his indigo 


402. What is said of the history of indigo ? Why was indigo forbidden to 
be used ? How is it now rendered a permanent color ? What are the sources 
of indigo ? How is it prepared from these plants ? Mention some of its prop¬ 
erties. What change does indigo undergo in contact with deoxidizing 



292 


ELEMENTS OF CHEMISTRY. 


vats. Five parts of powdered indigo, 10 of protosulphate of 
iron, 15 of hydrate of lime, and 60 of water, are agitated 
together in a close vessel and allowed to stand. The hydrat¬ 
ed protoxide of iron in conjunction with excess of lime, re¬ 
duces the indigo to the soluble state ; a yellowish liquid is 
produced, from which acids precipitate white or deoxidized 
indigo, which absorbs oxygen with the greatest avidity when 
brought in contact with the air. A Cloth steeped in the yellow 
solution, and then exposed to the air, acquires a deep and 
most permanent blue tint, by the deposition of solid, insoluble 
indigo in the substance of the fibre. Instead of the iron and 
the lime, a solution of caustic soda and grape sugar may be 
used. The sugar becomes oxidized, and the indigo reduced 
in the deoxidized state. Blue insoluble indigo is composed of 
Cj 6 H 5 N0 2 , and white, or reduced indigo, of Cj 6 H 5 N0 + H0. 
Under the action of heat and of reagents, indigo yields an ex¬ 
ceedingly numerous class of bodies. 

When the cloth is previously boiled in alum mordant, and 
then in a bath of indigo, mixed with any of the yellow dyes, 
a green color is obtained. Woof may be dyed violet , •purple 
or lilac, by means of cochineal, mixed with sulphate of indigo. 
The same colors are given to silk, by first dyeing crimson with 
cochineal, and then dipping the silk into the indigo bath. 
Cotton and silk are first dyed blue, then galled (with nut- 
galls), and soaked in a decoction of logwood ; but a more per¬ 
manent color is given by means of oxide of iron. Ivory is 
dyed blue by being immersed a longer or shorter time in a 
dilute solution of sulphate of indigo, mixed with a little potash. 
It assumes a blue tint of greater or less intensity, according 
to circumstances. Blue combined with red and yellow in 
cloth produces olive. 

403. Litmus is one of the colors employed by the dyer. 
To the chemist it is a reagent for acids, by which it is in¬ 
stantly reddened ; it then becomes a test for alkalies, by 
which its blue color is restored. It is prepared from a lichen 
that grows on maritime rocks, most abundantly in the Canary 
and Cape Yerd Islands. It is also prepared from a plant 
which is collected in Norway. It comes in friable, violet- 
colored, finely granular pieces. It has an alkaline smell and 


agents and with alkalies ? In what way does the dyer prepare his indigo 
vat 1 How do cloths steeped in this solution attain a deep and permanent 
blue ? How is a green color obtained ? How is wool dyed violet, purple, or 
lilac? W rite the composition of blue indigo ;—of white indigo. ’ 

403. What is said of litmus ? 



ORGANIC CHEMISTRY. 


293 


a saline taste. Test paper for chemical purposes is prepared 
with a watery infusion, consisting of one part of powdered 
litmus to 4 of water. This is applied by means of a brush to 
white unsized paper, or paper free from alum and other acid 
salts. The sheets, when dried, should be kept in close vessels 
in the dark. 

404. Cochineal is a little insect, the coccus cacti , which 
lives on several species of cactus, found in warm climates, 
and cultivated for this purpose in Central America, and the 
southern part of Mexico. The dried body of the insect yields 
to water and alcohol a magnificent red coloring matter, pre- 
cipitable by alumina and oxide of tin. Carmine is a preci¬ 
pitate of this kind. This substance is often adulterated with 
starch or vermilion, and is sometimes rendered paler by an 
excess of alumina used in its precipitation. This is detected 
by ammonia, which dissolves pure carmine, and leaves behind 
the substances with which it is adulterated. 

405. Madder is the most permanent and valuable of the 
red dye-stuffs. The plant from which it is obtained is a 
native of the South of Europe, and is cultivated in France 
and Holland. From the latter country most of the madder 
of commerce is procured. The coloring matter, which may 
be extracted from the root by several different processes, forms 
yellowish red acicular crystals, easily soluble in alcohol, but 
sparingly dissolved by boiling water. A purple or brown, and 
a yellow coloring matter also exists in madder ; the latter is 
very soluble in water. Even white flowers possess coloring 
matter. Many of them give a green with alkalies, although 
acids do not render them red. Some of them seem to contain 
the same coloring matter as yellow flowers. 

406. Brazil wood is much used for dyeing red. Logwood 
gives a violet, and, with a salt of iron, a black color. Its 
coloring-matter is called hematoxyline. Quercitron and 
fustic are two of the most important yellow dyes. 


ANIMAL CHEMISTRY. 

407. Life controls all other agencies in animal as well as 
in vegetable chemistry. These two departments approach 

404. Whence is cochineal obtained ? What is carmine ? 

405. What is said of madder? Whence is it obtained ? Mention some of 
its properties. What is said of the coloring matters of white flowers ? 

406. What other dye woods are mentioned ? 

407. What is said of the agency of life in animal chemistry ? In what re- 





294 


ELEMENTS OF CHEMISTRY. 


each other so nearly, that it is hardly possible to decide 
whether some of the species belong to the animal or vegetable 
kingdom ; still, in the great majority of cases we observe the 
following characteristic differences : 

1. The combinations produced by the principle of life in 
the animal organization, ar e far more complex than those pro¬ 
duced in the vegetable kingdom. Not only the structure of 
the bodies of animals, but their chemical composition, is far 
more complex than those of the forms of vegetable life. 

2. The great mass of vegetable substances consists of non- 
azotized substances, consequently of substances which contain 
only three elements ; hut in the animal body, the azotized 
and the sulphurized substances predominate. Water and fat 
are almost the only substances composed of two or three 
elements that occur in the animal body ; all the others, as 
flesh, cartilage, blood, hair, nails, &c., are rich in nitrogen, 
sulphur, and also contain phosphorus. 

3. Most animal substances, when viewed under the micro¬ 
scope, exhibit the form of small globules. In the mineral 
kingdom, the angular (crystalline) form prevails. The vege¬ 
table kingdom, holding a middle position between the animal 
and the mineral, affords examples of both kinds of forms, viz., 
the globular or spherical, in starch, yeast, &c., the crystalline 
in sugar, organic acids, bases, &c. 

4. The elements of which animal substances are formed, 
are exactly the same as those which occur in the vegetable 
kingdom, ' viz., oxygen, hydrogen, carbon, nitrogen; also 
sulphur, phosphorus, and chlorine, and the metallic sub¬ 
stances, calcium, potassium, sodium and iron. 

5. The agency of cellular action, (p. 230,) in the animal 
body, is much more feeble and more limited than in vegeta¬ 
ble life. In the vegetable world, by the action of cells, all 
the substances visible in the plant are produced out of purely 
inorganic matter. In an animal this agency is confined to 
the modification or change of complex organic principles 
already existing ; principles which owe their origin to plants. 
A building up, an organizing power, is indeed manifest, but 
the materials are furnished, as it were, to its hand, in a state 
requiring an exertion of chemical force infinitely less energetic 
than that required to produce woody fibres, or sugar from car- 


spects are animal organizations more complex than vegetable forms ? What 
is the second difference between animal and vegetable substances ? What is 
the third difference ? What have animal and vegetable substances in com- 




ORGANIC! CHEMISTRY. 


295 


tonic acid and water. The most intricate and refined 
changes are produced by vegetable life, changes incompre¬ 
hensible in their nature, though evident in their effects ; they 
are in the ascending scale, producing organic substances from 
inorganic. The changes which oceur in the animal body 
are chiefly in the descending scale, forming compounds less 
and less complex by changes which we can in most instances 
understand, and in some imitate, until they at length- reach 
the inorganic condition, and once more beeome capable of 
assimilation by plants. A perpetual and unbroken chain of 
agencies is thus established, the producls of the one order of 
beings becoming the sustenance of the other. 

The following table is useful as a general outline of the 
differences in the functions of animals and plants. Not all 
animals produce carbonic acid, for several kinds of animal- 
eulae have been discovered which decompose carbonic acid, 
and give off vast quantities of oxygen to the atmosphere: 


The vegetable 

Prodaces neutral azotized substances, 
“ fatty substances, 

u sugar, starch and gum. 

Decomposes carbonic acid, 

“ water, 

" • ammoniacal salts, 

Disengages oxygen. 

Is an apparatus of reduction. 

Is stationary. 


The animal 

Consumes neutral azotized substances, 
■“ fatty substances, 

“ sugar, starch and gum,' 

Produces carbonic acid, 

“ water, 

■“ ammoniacal salts. 

Absorbs oxygen, 

Is an apparatus of oxidation. 

Is locomotive. 


6. The vital principle produces a continual equilibrium, 
in the animal frame. This is also the case in all organic 
life, but in animal life it is pre-eminently true. Without a 
constant repair or renewal of the whole animal system by 
deposition and organization of matter from the blood, the 
body would soon waste away. This organization of matter 
is self-regulating, or varies with the demands of the system, 
so that, though in circumstances always changing, and ex¬ 
periencing within itself continual changes, amounting to many 
hundred pounds in the course of a year, the animal frame 
preserves its weight from year to year very nearly the same 
in amount. Art is far outdone, and must ever be, for no con¬ 
trivance of man is destined to a perpetuity beyond the 
materials of which it is at first constructed. 


mon to a great extent ? What is said of the agency of cellular action in the 
animal body ? How do the changes which occur in the animal body compare 
with those produced in vegetable substances 1 What is said of the action of 
the vital principle in maintaining an equilibrium in the animal frame ? What 




296 


ELEMENTS OF CHEMISTRY. 


7. The food of animals consists for the most part of organ¬ 
ized matter , while that of vegetables is derived from the in¬ 
organic kingdom. The inorganic constituents of vegetables 
are derived from the soil, and from the decomposition of other 
vegetables, which, by decay, fermentation, or putrefaction, 
lose their organic character, and are resolved into their in¬ 
organic elements. 

8. The food of the two great classes of animals, the gram- 
iniverous, or the vegetable feeders, and the carniverous, is 
composed of essentially the same principles. Yegetable al¬ 
bumen, fibrine, and caseine, the food of the former class, are 
in composition identical w r ith bodies of the same name ex¬ 
tracted from blood and milk, and which are the food of the 
latter class of animals. 

constituents of the animal body. 

408. Fibrine , C 4 0 0 H ?1 0 0 12 0 'N 5 6 -f- PS, according to 
Mulder. This substance is found in two distinct conditions 
in the living animal ; in the blood, where it is dissolved, per¬ 
fectly fluid, and in the muscular flesh, of which it forms the 
characteristic ingredient. In the latter it is solid and in¬ 
soluble, or coagulated. When a thin slice of muscle is wash¬ 
ed in cold water until perfectly white, it is seen to consist of 
a stringy-looking substance, which is the fibrine itself, travers¬ 
ed in all directions by blood-vessels, nerves, and membranous 
matter. Fibrine is also deposited when the expressed juice 
of plants, such as beets, turnips, &c., is allowed to stand. 
This appears in every respect the same with animal fibrine. 
The latter is usually prepared by beating fresh-drawn blood 
with twigs, and washing the clot which adheres to the twigs 
with water and ether. It may also be prepared by putting 
some blood into a well-stoppered bottle 4 and agitating it with 
some pieces of lead or tin. In a fresh state it forms long, 
white, elastic filaments, which, under the microscope, appear 
to be composed of small globules, arranged in strings j it is 
quite tasteless,^and insoluble in both hot and cold water. By 
long-continued boiling it is partly dissolved. When dried in 


is the difference between the food of animals and that of plants ? Whence are 
the inorganic constituents of plants derived ? In what respects is the food of 
all classes of animals alike ? 

408. W rite the formula for fibrine. How much carbon is there in 4,417 
parts of fibrine ?—how much hydrogen 1 —how much oxygen ?—how much 
phosphorus 1 —how much sulphur ? How does this substance occur in the 
animal body ? How may vegetable fibrine be obtained ? How does this 



ORGANIC CHEMISTRY. 


297 


vacuo, or at a gentle heat, it loses about 80 per cent, of water, 
shrinks very much in volume, and becomes translucent and 
horny. When again moistened, it recovers, for the most part, 
its former bulk. 

The fibrine of arterial and venous blood is not absolutely 
the same. When the venous fibrine of human blood is trit¬ 
urated in a mortar with 1|- times its weight of water, and i 
its weight of nitrate of potash, and the mixture left twenty- 
four hours or more at a temperature of 100° to 120°, it be¬ 
comes gelatinous, and exhibits all the properties of a solu¬ 
tion of albumen which has been neutralized by acetic acid. 
It eventually becomes liquid. Arterial fibrine, treated in the 
same way, does not become liquid, nor does the fibrine of 
venous blood when long exposed to the air or to oxygen. 
The fibrine of muscular flesh resembles that of venous blood. 

409. Albumen, C 4 0 0 H 31 0 0 12 0 N 5 0 PS 2 . This formula is 

the same with that of fibrine, with the exception of S 2 , in¬ 
stead of S. in fibrine. White of egg, and the clear serum, 
or fluid part of the blood, contain albumen, associated with 
soda, from which it may be obtained by neutralizing the soda 
with acetic acid, and by diluting with cold water. The pre¬ 
cipitate of albumen thus formed is soluble in water contain¬ 
ing a minute quantity of alkali. By a sufficient heat, al¬ 
bumen coagulates and becomes a white body, wholly in¬ 
soluble in water. With metallic salts, as corrosive sublimate, 
it gives insoluble precipitates ; hence its use as an antidote 
for that poison. 1 

After the fibrine is removed from the expressed juice of 
plants, by the process mentioned above (408.), if the tempera¬ 
ture of the juice be raised to 212°, it becomes a second time 
turbid with vegetable albumen . A third principle is obtain¬ 
ed after the albumen is separated, by slowly evaporating the 
solution. This is vegetable caseine which appears in a film 
on the surface. 

410. Caseine, C 40O H 310 O 120 :N' S0 S, is found only in milk, 
where it exists in a state of perfect solution, owing, like al¬ 
bumen, its solubility to a small quantity of alkali. Unlike 


compare with animal fibrine? How is animal fibrine usually prepared ? 
Mention some of its properties. How is it shown that arterial differs from 

venous fibrine ? , _ . „ . e , 

409. Write the formula for albumen. How does this formula diiiei fiom 
that of fibrine ? Where is albumen found ? How may it be obtained from 
these substances? Why is it used as an antidote for corrosive sublimate ? 
How mav vegetable albumen and vegetable caserne be obtained/ 

410. Write the formula for caseine. How does this formula differ fromthat 
of fibrine and that of albumen ? Where is this substance found ? Why is 

13* 





298 


ELEMENTS OF CHEMISTRY. 


albumen, however, caseine is not coagulated by heat. The 
addition of a little acid of almost any kind, precipitates 
caseine from milk, by neutralizing the alkali which held it in 
solution. An exceedingly small quantity of acid will ef¬ 
fect the precipitation when the reaction is aided by a gentle 
heat. 

A solution of caseine may be coagulated by certain animal 
membranes. On this principle, the manufacture of cheese 
depends. A piece of the lining .membrane of the stomach of 
an animal, more particularly that of a young animal, as a 
calf, is cleaned by slight washing in cold water, plunged into 
a large mass of milk, and the temperature of the whole slowly 
raised to about 120° or a little higher. At a particular mo¬ 
ment the milk undergoes a very complete coagulation. It 
separates into solid, white, opaque curd, and into thin, pale- 
colored, translucent whey. The former consists chiefly of 
caseine and butter, the latter of water, holding in solution 
most of the saline compounds of the milk, together with 
milk sugar, to which it owes its sweetness. The curd is 
drained, mixed with salt, and sometimes other condiments, 
and then undergoes various manipulations, the principal object 
of which is to communicate consistence and form, and to get 
rid of superfluous moisture. The cheese thus formed is allow¬ 
ed to remain in a cool situation for several months, and un¬ 
dergoes a particular kind of putrefactive fermentation, upon 
which its flavor and value depend. 

The following table gives the composition of several 
varieties of cheese, of which No. 1 is skimmed milk cheese. 
One hundred pounds of cheese contain— 



No. 1. 

No. 2. 

No. 3. 

No. 4. 

Water, 

43-82, 

35-81, 

38-58, 

38-46. 

Caseine, 

4504, 

•37-96, 

25-00, 

25-87. 

Butter, 

5-98, 

21-97, 

50-11, 

31-86. 

Ash, 

5-18, 

4-25, 

6-29, 

3-81. 


From this table it appears that cheese contains from i to 
i its weight of water, and also, with the exception of skimmed 
milk cheese, from £ to i of butter. 


caseine dissolved in milk ? Is caseine coagulated by heat ? How may this 
substance be precipitated from milk? Upon what does the manufacture of 
cheese depend ? Into what two portions is the milk separated ? Of what 
does caseine consist ?—whey ? How is cheese prepared from the curd ? 
How much water does cheese contain ? How much butter ? What kind of 



ORGANIC CHEMISTRY. 


299 


Skimmed milk cheese, on the other hand, contains the 
largest amount of caseine, amounting to nearly half of its 
weight. This renders this kind of cheese very nutritious, 
while it is not as rich as the other kinds, and therefore might 
well form a principal article of diet. 

Fibiine, albumen and caseine are very nearly alike in their 
composition, as appears from their formula): 


C 

C 

C 


4 0 6^3 10^12 0^5 1)^' = 10 Pr.+PS. 

4 0 0^3 10^12 0^5 0^2 ~ lOPr.-j-PSg. 
4 0 0 ^3 10^12 0^5 0 + S. = 10 Pi'. -pS. 


In these formula), C, H, 0, FT, are the same, and in the 
same proportions. From this it is supposed that these ele¬ 
ments form a substance to which the name proteuie has been 
given, although this has never been entirely isolated. Mulder, 
its discoverer, assigns to it the formula C 4 0 H 3 jN 5 0 12 =Pr. 
With proteine, phosphorus and sulphur are supposed to be 
combined, forming fibrine, albumen, or caseine, according to 
the proportions in which they unite with proteine. Hence, 
these three substances are called the 'proteine group. 

411. Gelatine is obtained from animal membranes, skin, 
tendons, and bones. These dissolve in water, at a high tem¬ 
perature, more or less completely, but with very different de¬ 
grees of facility, giving solutions which, on cooling, acquire 
a soft, tendinous consistence. This substance is termed gela¬ 
tine. The coarser forms from hoofs, hides, &c., are called 
glue ; that from skin and finer membranes is known as size ; 
and the purest gelatine from the air bladders, and other 
membranes of fish, is called isinglass. Gelatine does not pre¬ 
-exist in the animal tissues, but is generated from the mem¬ 
branous tissue by the action of hot water. 

After being taken from the moulds, glue is cut up by a fine 
brass wire, and placed to dry upon packthread nettings, which 
give to it the common grooved appearance. It contracts 
very much in drying, and becomes a glassy and brittle mass. 
A concentrated solution of alum is sometimes mixed with 
melted glue to render it whiter, and to thicken it without 


cheese contains the most caseine ? What is said of skimmed milk cheese 1 
What foux- elements are in the formulae of caseine, albumen, and fibrine, in 
the same proportions ? What is infen-ed from this fact 1 What are these 
three bodies called? 

411. In what substances is gelatine found in a state of great purity? 
What circumstances affect the amount of gluten in wheat ? What is the 
quantity of gluten in wheat? What circumstances influence it? Whence 



300 


ELEMENTS OF CHEMISTRY. 


apparently diminishing 1 its tenacity. It is always added in large 
quantities to size. Alum is used for the same purpose in 
clarifying various kinds of liquors and ■preserves. The ad¬ 
hesive power of glue is much increased by adding to it white 
lead or borax (about 1 oz. or 1^-oz. to 1 lb. of glue). Long- 
continued boiling gradually alters it, and the solution loses 
the power of forming jelly on cooling. One part of dry gela¬ 
tine dissolved in 100 parts of water, solidifies on cooling. 
With tannic acid,* or infusion of galls, it gives a copious, 
curdy precipitate, which coheres on stirring to an elastic 
mass quite insoluble in water, and incapable of putrefaction 
(p. 250). 

The gluten of wheat generally varies from 7 to 10 per cent, of the 
grain, although the amount varies greatly with circumstances. 1st. 
Wheat grown in calcareous soils generally contains more gluten than 
that produced on soils abounding in organic matter. 2d. The wheat 
of warm climates generally contains more gluten than that grown in 
colder latitudes. Some specimens of wheat, the growth of a warm 
climate, yielded 28 per cent, of gluten. 8d. The gluten of wheat varies 
with the kind of seed, and the mode of culture. One variety of wheat 
grown in the Botanic garden at Paris, gave 26*7 per cent, of gluten, while 
the same kind, when grown in the open fields at Alsace, gave but 17*3 
per cent. 4th. The time of cutting affects the composition of wheat. 
The grain from a portion of a field cut 26 days before the crop was 
fully ripe, gave 9*3 per cent, of gluten; that from a second portion 
cut 10 days before ripeness, gave 9*9 per oent.; and that from a third 
portion cut when the crop was fully ripe gave 9*6 per cent. 5th,— 
The gluten of wheat, like the constituents of most plants, is greatly 
affected by the kind of manure which the crop receives. Rye con¬ 
tains from 9 to 13 per cent, of gluten, Indian corn 12, barley 3 to 5, 
oats 2 to 5, buckwheat 10, potatoes 3 to 4, beans 10, red beets 1*3, 
turnips 0*1, cabbage 0*8. 

412. The blood , respiration . The blood is the general, 
circulating fluid of the animal body, the source of all nutri¬ 
ment and growth, the general matter from which all secre¬ 
tions, however much they may differ in properties and com¬ 
position, are derived. Food or nourishment can only be made 
available by being first converted into blood. It serves also 
the scarcely less important office of removing from the body 
principles which are no longer required. 


is gelatine obtained? What names are applied to the different kinds of it? 
How is it prepared? For what purpose is alum used with it ? What effect 
has a solution of tannic acid upon gelatine ? 

„ 412. Mention some of the purposes which are served by the blood. Explain 
hgs^lOp and 104. What is said of the temperature of the blood ? Of what 
kinds is blood composed ? What is said of the arterial blood ?—of venous 



ORGANIC CHEMISTRY. 


301 


While circulating in the vessels, blood consists of a nearly 
colorless and transparent liquid, in which 
float myriads of minute, vesicular bodies, 
or corpuscles, of which by far the greater 
number are of a bright red color, (Fig. 

103.) These are so small as to be in¬ 
dividually quite invisible to the naked 
eye, and therefore give the blood the ap¬ 
pearance of a homogeneous red fluid. 

Besides the red corpuscles, there are al¬ 
ways present a few colorless particles 

1 • • ■, r t t • • Blood corpuscles magnified 

■having irregular lorms, and ditiering in 40 a diameters. 

other respects from the red corpuscles. 

These bodies are found to present different appearances in 
the Wood of different animals. In the mammifers they are 
round, red or yellowish discs; in birds, 
lizards, frogs and fish, they are elliptical. 104 * 

In magnitude they differ with the genus 
and order , although quite constant in 
members of the same species. The red 
corpuscles of the human blood vary from 
soV^ to 2 oV¥ an inch. in diameter, 
while in the frog the longer diameter of 
the ellipse measures at least four times 
as much. In some of the lower orders' 
of animals the blood is entirely devoid 
of redness, and nearly colorless. This is White corpuscles of the blood 
called white blood. With white-blooded magnified 400 diameters, 
aftiinals the muscles are also white, as with fishes, frogs, 
reptiles, her. 

• The temperature of the blood in all vertebrated animals is 
above that of the medium in which they live. In the mam¬ 
malia this is very apparent, but in birds still more so. The 
heat of the blood is dependent upon respiration, and is pro¬ 
portioned to its activity. In man it does not vary much from 
98°, even under great vicisitudes of climate, provided the 
system be in a healthy state. In birds it is sometimes as high 
as 190°. This blood consists of two kinds, which differ con¬ 
siderably, viz., that contained in the left side of the heart and 
* in the arteries generally , and that contained in the right side 
and in the veins. The arterial blood is blight red ; the ve- 




blood ? How do oxygen and carbonic acid act on the blood corpuscles ? 
What reason is assigned for the change of color in the blood 1 What is said 




302 


ELEMENTS OF CHEMISTRY. 


nous blood is dark claret-colored, sometimes approaching to 
black. The blood streams out of the left side of the heart 
through the arteries into all parts of the body, from which it 
returns dark-colored through, the veins to the right side of 
the heart. Before it recommences its circulation, it is impelled 
through the lungs, in which it comes in contact with the air. 
It was formerly believed that the dark color of venous blood 
was owing to the presence of an excess of carbon, and that 
the oxygen of the air, by combining with this excess, restored 
the scarlet color. It is now considered probable, however, that 
this results chiefly from a change in the form of the blood cor¬ 
puscles produced by oxygen, causing them to collapse and be¬ 
come concave. Carbonic acid, on the other hand, which is 
present in the venous blood, causes these corpuscles to swell, 
and become nearly spherical. It is thought that the iarger 
number of red rays reflected in the former case is the reason 
of the change produced in the color of the blood by coming 
in contact with air. Probably, however, the chemical action 
of oxygen has also an influence in producing this result. 

In its ordinary state the blood has a density varying from 
1-053 to 1-057. It feels slimy, and has a decidedly alkaline 
reaction. It has a saline and disagreeable taste, and, when 
quite fresh, a peculiar odor, or halitus, which almost imme¬ 
diately disappears. An odor may, however, afterwards be 
developed by adding sulphuric acid, and this odor is by some 
considered characteristic of the animal from which the blood 
was obtained. 

One of the most remarkable peculiarities of the blood is its 
spontaneous coagulation when separated from the body. The 
fibrine of the blood is held in a state of solution* while cir¬ 
culating in the vessels, but no sooner is the blood removed 
from the system, than it begins to separate in the solid state, 
after which it becomes quite insoluble in water. If this co- 
agulum be placed upon bibulous paper, and drained as much 
as possible from the fluid portion, and then put into water, 
the coloring matter dissolves, forming a magnificent crimson 
solution. This is called hematozine. It contains albumen 
and coagulates by heat, and by addition of alcohol, but can¬ 
not be separated from the albumen. Hematozine differs from^ 
the other animal principles, in containing as an essential 
ingredient oxide of iron. A solution, rich in oxide of iron, 
may be obtained from the dried clot of blood, by calcining it 

of the coagulation of blood ? What is hematozine? In what respects does it 
differ from the other animal principles ? How is the healing of wounds pr^ 



ORGANIC CHEMISTRY. 


303 


in a crucible, and digesting with dilute hydrochloric acid. 
The healing of wounds is produced by the coagulation of the 
fibrine of blood, and furnishes one of the most striking proofs 
of design in the construction of the human frame. When an 
incision, or laceration of the body happens, the blood issues 
from the divided vessels, fills up the wound, and then coag¬ 
ulates, unless a very large vessel should be opened, and the 
blood flow too rapidly and escape. The clot remains while 
the serum evaporates. Organization then takes place in the 
fibrine ; that is, new blood-vessels are formed in it, con¬ 
nected with the adjacent old ones ; new nerves are also pro¬ 
duced through it, and it soon becomes a living mass. Rest 
and quiet are all that nature requires to complete the pro : 
cess, and the simplest dressing of the wound is therefore all 
that is needed. 

The composition of human blood varies continually in a 
greater or less degree. It cannot, therefore, be determined, 
except for the individual and the time . The slightest cause, 
as for instance, drinking water freely, will effect an entire 
change in the analysis of the blood of individuals. The fol¬ 
lowing table will, however, give a general idea of the con¬ 
stitution of the blood : 

In 1000 parts of healthy male and female blood were contained: 


Male. Fe'male. 

Water, - - - 779-0. 791-1. 

Fibrine, - - - 2-2. 2-2. 

Fatty matters, - - 1-60. 1-62. 

Albumen, - - 69-4. 70-5. 

Blood-corpuscles - - 141-1. 127-2. 

Extractive matters and salts, 6-8. 7-4. 


Hence it will be seen that female blood differs materially from that of the 
male in the amount of water and of blood-corpuscles. 

The presence of saline matter and albumen in the blood 
prevents the solution of the red corpuscles. These are very 
easily soluble in water, and the limit of dilution within 
which they can remain uninjured, is nearly reached in the 
blood, for, when water is added, they are immediately at¬ 
tacked. . - ■ 

413. The lungs are made up of an immense number oi 
cells connected with the windpipe. In the act of respira¬ 
tion they are perfectly passive, the air being introduced and 


duced by the coagulation of blood ? _Whv are not the red corpuscles dissolved 

iQ 413 Whatsis said of the lungs ? Explain fig. 105 How do inhabitants of 
very cold countries maintain the temperature of their bodies? 





304 


ELEMENTS OF CHEMISTRY. 


expelled alternately by the contraction of the muscles of the 
chest. The manner in which this is done may be understood 
from Fig. 105. Let the glass globe A represent the capacity 
of the chest; b, b, are sheets of gum-elastic stretched over 
openings in the globe. B is a bladder introduced 
Fig. 105. j nto t0 p 0 f the globe, and tied over the neck in 
such a manner that the air can enter within the 
bladder, but not within the globe. If now the 
sheets of gum-elastic b, b, be drawn out by the 
strings attached to the centre of these sheets, the 
capacity of the globe will be enlarged, and, con¬ 
sequently, the air within will be rarified. The 
external air, therefore, rushes into the bladder 
through the top, and dilates it exactly in proportion 
as b, b, are drawn out. If b, b, are now allowed to contract 
and return to their former position, the bladder will also con¬ 
tract and become flaccid as at first. In a similar manner, 
when the cavity of the chest is enlarged, the air rushes into 
the lungs, which are suspended in the chest like the bladder 
in the glass globe, and when this cavity is diminished, the 
air is forced out. The capacity of the chest is enlarged both 
upwards and downwards ; upwards by muscles, the contrac¬ 
tion of which draws the lower ribs upwards and outwards; 
downwards by the contraction of the diaphragm, which covers 
the bottom of the chest. 

The number of respirations averages about 17 each minute, 
and at each respiration, about 17 cubic inches of air are in¬ 
troduced. By a forced effort, 50 or 60 cubic inches may be 
expelled. About seven tons of blood are daily exposed to 
226 cubic feet of air. Inhabitants of very cold countries 
maintain the temperature of the body, by consuming enor¬ 
mous quantities of food of a fatty nature, the carbon and hy¬ 
drogen of which are chiefly employed in the production of 
animal heat. These people live by hunting, an occupation 
that requires great muscular exertion, and consequently, 
quickens and deepens the breathing, while from the increased 
density of the air of those regions, a greater weight of oxygen 
is taken into the lungs, and absorbed into the blood at each 
inspiration. In this manner the temperature of the body is 
kept up, notwithstanding the piercing cold. 

414. The skin is an elastic substance, covering the whole 
body. It consists of a thick tissue of cells, between which 


414, Of what does skin consist? Explain %. 106. What is the office of 
the pores ? 




) 


ORGANIC CHEMISTRY. 305 

are small openings (pores). Fig. 106 represents a piece of 
human skin, as magnified by the mi¬ 
croscope. Through these pores a sub- Fig. 106 - 

stance, partly oily and partly watery, 
is separated, together with some car¬ 
bonic acid. There is a slight differ¬ 
ence in the composition of the finely- 
organized and highly-elastic mem¬ 
brane, which forms the coat of the 
arteries, and the coarse epidermis of 
the foot, as will be seen from the fol¬ 
lowing analysis : 



Artery coat. 

Epidermis. 

Carbon, 

53.75, 

5104. 

Hydrogen, 

7-08, 

6-80. 

Nitrogen, 

15-36, 

17-23. 

Oxygen, 

23-81, 

24-93. 


100 .00, 

100 -00. 


A little sulphur was found in the epidermis. Hair, horn, 
nails, wool, and feathers, have a similar composition. They 
all dissolve in caustic potash with disengagement of ammonia, 
and the solution, when mixed with acid, deposits a kind of 
proteine (p. 299) common to the whole. 

In an experiment tried on a healthy individual, it was 
found that 14 oz. of carbon were given off in the state of car¬ 
bonic acid in 24 hours, from the lungs and the skin. During 
the same time a horse consumed in respiration 77 ounces, 
and a cow 70 ounces. 

415. Milk, when examined by a microscope of even 
moderate powers, appears to consist of a perfectly transparent 
fluid, in which float numbers of trans¬ 
parent globules, which consist of fat 
(Fig. 107). The size of these glob- 
•ules varies from a mere point to 
about -^oVtf °f an inch in diameter, the 
average size being rather more than 
4 oVo an inch. The milk which is 
obtained during the first few days of 
lactation, is always much richer than 
ordinary milk. In this we find, in 
addition to the common milk globules, numerous granular 


Fig. 107. 


°o 



415. Of what does milk consist? Explain figs. 107 and 108. What is 










306 


ELEMENTS OF CHEMISTRY. 


corpuscles (Fig. 108) of a pale, yellowish color, and con¬ 
siderably larger than the others, 
their diameter varying from 2 oV o 
to -g-io °f an “ ic h- 

When suffered to remain at rest 
for some hours, at the ordinary 
temperature of the air, a large 
proportion of fat globules collect 
at the surface in a layer of cream. 
If this be now removed, and ex¬ 
posed for some time to strong agi¬ 
tation, the membranes of the oil 
globules are torn, they coalesce 
into a mass, and the remaining watery liquid is expelled 
from between them. The butter so produced must be 
thoroughly washed with water, to remove as far as possible 
the last traces of caseine, which readily putrifies, and would 
in that case spoil the butter. A little salt is usually added. 
The butter thus prepared is not entirely free from butter¬ 
milk, and, therefore, cannot be preserved a great length of 
time, without being clarified by fusion. The watery part 
then subsides, and carries with it the residue of the azotized 
matter. This process, unfortunately, impairs the flavor of 
the butter, and is not, therefore, generally adopted. The pro¬ 
portion of margarine and oleine in butter, on which depends 
its consistence, varies with the season, or rather with the 
kind of food. In summer the oily portion is more considerable 
than in winter. In a fresh state, when taken from a healthy 
animal, milk is always feebly alkaline. When left to itself, 
it soon becomes acid, and is found to contain lactic acid, 
which cannot be discovered in the fresh condition. The 
alkalinity is due to the soda which holds the caseine in 
solution. In this soluble form, caseine possesses the power 
of taking up and retaining a considerable quantity of phos¬ 
phate of lime. The density of milk varies exceedingly, and 
its quality usually bears an inverse ratio to its quantity. By 
feeding on certain kinds of food, the quantity is often increas- 


Fig. 108. 



cream ? How is butter produced ? How may butter be preserved a great 
length of time ? Has fresh milk alkaline or acid properties ? To what is the 
alkaline character of fresh milk owing? Why is phosphate of lime dissolved 
in milk ? What acid is produced in milk on standing ? What is said of the 
density of milk ? 



ORGANIC CHEMISTRY. 


307 


ed at the expense of the quality An analysis of cow’s 
milk gave the following result : 


One thousand parts of milk contained : 


Water, 873-00. 

Butter, 30-00. 

Caseine, 48-20. 

Milk-sugar, 43-90. 

Phosp. lime, 2-31. 


Phos. magnesia, 

“ iron, 

Chloride of potassium, 
“ sodium, 

Soda, 


0-42. 

0-07. 

1-44. 

0-24. 

0-42. 


• 416. The 'production of fat is increased by a state of rest, 

a warm situation, and an abundant supply of food. Every 
part of the body is wasting away, but this waste takes place 
much more rapidly by exposure to cold, or with active exer¬ 
cise. The fat of an animal is a provision of nature for the 
maintenance of life during a certain period of privation. This 
may be produced by the vital energies from food that contains 
no fat; thus bees will produce wax, though fed upon pure 
sugar. Still the assimilation of fat takes place much more 
readily from food in which it is already contained, and hence 
this deposition, and the production of butter, from the milk 
of an animal, hear a certain relation to the amount of oleagin¬ 
ous matters found in its food. For this reason, Indian corn, 
which contains from 8 to 12 per cent, of oil, furnishes one of 
the most valuable articles for feeding and fattening cattle. 
Oil cake , or the residue of linseed-oil factories, produces a 
still more striking effect in fattening cattle. 

417. Bones consist of an animal and an earthy matter 
(phosphate of lime, bone earth). Bones also contain from 
6 to 7 per cent, of carbonate of lime. The 
amount of this substance in bones is determin¬ 
ed by the arrangement represented in Fig. 109. 
A small portion of the pulverized bone is put 
into the flask, a. This flask contains a little 
water, and a small tube, c , holding hydrochloric 
acid. A chloride of calcium tube, b , is attached 
to the cork. The whole apparatus is now 
weighed, after which the acid is allowed to flow 
gradually out of the tube, c, by inclining the flask. The 
dilute acid thus formed in a acts upon the pulverized bone, 
and expels its carbonic acid. This passes off through the 
chloride of calcium tube, b, by which it is deprived of its 
moisture, and thus nothing but carbonic acid escapes from the 



416. What circumstances tend to increase the production of fat ? What. 
is the object of fat ? 

417. Of what do bones consist? Explain Fig. 109. In what respect does 




308 


ELEMENTS OF CHEMISTRY. 


apparatus. The amount of this gas is, therefore, what is 
lost, which may he determined by weighing the apparatus 
again, and comparing the second with the first. From the 
amount of carbonic acid thus determined, that of the car¬ 
bonate of lime may be ascertained, for 50 parts of carbonate 
of lime contain 22 parts of carbonic acid, and the weight ob¬ 
tained must therefore be increased in the proportion of 
50 to 22. 

The following table shows the composition of the bones of 
an adult, compared with those of a child : 


Femur, 

Inorganic matter. 

Adult. Child. 

62.49 57-51. 

Organic matter. 

t - A —\ 

' Adult. Child. 

37-51 42-49. 

Humerus, 

63-02 

58-08. 

36-98 

41-92. 

Radius, 

60-51 

-56*50. 

36-49 

43-50. 

Os temporum, 

63-50 

55-90. 

36-50 

44.10. 

Costa, 

57-49 

53.75. 

42-51 

46.25. 

From this table it appears that the bones of the adult are 


in every instance richer in earthy salts than those of a child. 
During the earliest periods of life, they consist almost entirely 
of gelatinous membranes, having the form of the bones, but 
of a loose, spongy texture. The cells or. cavities of this 
texture are afterwards filled with phosphate of lime, and by 
the gradual acquisition of this salt, the bones acquire hardness 
and durability. A portion of the phosphate, after the bones 
of the infant hav6 been sufficiently expanded and solidified, 
is deposited in the teeth, which consist at first only of a gel¬ 
atinous membrane, or case, fitted for the reception of this salt. 
After acquiring hardness within the gum, the new-formed 
tooth protrudes from it. 

In some quadrupeds, the phosphate of lime is deposited 
likewise in their horns. When animals have arrived at a 
state of maturity, and their bones have acquired sufficient 
solidity, the phosphate of lime which is taken with the food 
is seldom assimilated, excepting when the female nourishes 
her young with milk ; it is then assimilated in the milk for 
them, to strengthen and complete their bones. 

418. Relations of chemistry to common life. In the brief 
survey which we have now taken of this most extensive 


the composition of the bones of a child differ from that of the bones of an 
adult ? 

418. What is said of the relations of chemistry to common life ? How does 
this subject illustrate the wisdom and goodness of the Creator ? . 





ORGANIC CHEMISTRY. 


309 


science, we have found every part intimately connected with 
life. In inorganic chemistry, we have been led to the compo¬ 
sition, and, in a degree, to the forms of vegetable and animal 
structures ; we have followed the principle of life in its or¬ 
ganization of the animated world around us, and of our own 
frames. In organic chemistry we have become acquainted 
with the nature and properties of bodies, which, either in their 
simple state, or in combination with other bodies, we are con¬ 
stantly meeting with, and employing in the various processes 
of art, of agriculture, of domestic economy, or in medicine. 
While such is the wide range of this science, there is none 
that so thoroughly investigates the bodies which are the ob¬ 
ject of its study. The atoms of these bodies are its appro¬ 
priate study, and all its investigations are founded, not upon 
the laws which control masses, but upon those which govern 
the ultimate particles of bodies. Hence, its knowledge is 
complete; so far as explored, the subjects of its study are 
thoroughly known. 

In this thorough investigation of nature, we find no fault 
to mar the beauty or perfection of her works. The smallest 
atoms are obedient to laws of perfect wisdom, and every com¬ 
pound which these atoms form, is perfect in its construction 
and in the properties by which it is related to other bodies. 


EXPERIMENTS. 



| ptg°The numbers correspond to references in the text. 

(1.) Freezing mixtures; snow 4 drams, chloride of calcium (pulverized) 
5 drams,—this mixture freezes mercury, and the thermometer sinks from 
32°-f-to—40° ;—snow 2 drams, chloride of calcium 3 drams,—this mix¬ 
ture freezes nitric acid, and the thermometer sinks from 15°-f-to—68° ;— 
snow 8 drams, sulphuric acid (diluted) 10 drams,—freezes almost every 
known liquid; alcohol, however, is said to require a freezing mixture 
of—110°. .When the thermometer is reduced by the last mixture to— 
68 °, it may be reduced by this to—91°. 

(2.) Bengal lights; nitre 28 oz., sulphur 12 oz., realgar or orpiment 
(306.) 2 1-2 oz.; or nitre 6 oz., sulphur 2 oz., orpiment 1 oz.; or nitre 6 
oz., sulphur 2 oz., sulphuret of antimony 1 or 2 oz. Indian white fire ; 
dry saltpetre 24 parts, dry sulphur 7, fine dry charcoal 1 ; or realgar 2 
parts instead of the charcoal. The“whole should be intimately mixed 
and cautiously dried near, the fire or over a stove. Chinese fire ; meal 
powder (crushed powder) 1 lb., sulphur 2 oz., sulphuret of iron 2 oz., or 
meal powder 1 lb., sulphuret of iron 4 oz. Port fire ; nitre 4 oz., sul¬ 
phur 2 oz., gunpowder 1 oz. Roman candles ; saltpetre 2 1-2 lb3., meal 
powder, glass dust, and sulphur, each 1-2 lb. Red and green fire are 
very difficult to make, but they may be purchased cheaply at Chilton’s, 
in New York. The volume of flame in these fire works may be greatly 
augmented by the addition of a little Canada Balsam. 

(3.) Sulphuric acid 1 oz., water 1 oz. This mixture will boil water 
in a glass tube. Concentrated sulph. acid dropped into water causes a 
hissing sound like red hot iron.—Rub together sulphur and potash in 
equal parts; they unite with heat, and form sulphuret of potash.— 
Add 1 oz. of hydrochloric acid to 1 oz. of ammonia, great heat will be 
produced by the mixture. Most intense heat is produced when 1-2 oz. 
of hydrofluoric acid is added to an ounce of water. This acid should be 
poured from a leaden bottle attached to a stick, four or five feet long, 
and the cup containing the water, should stand on the hearth.—Add 
water to quicklime (p. 170.) Greater heat is produced by adding sul¬ 
phuric acid to lime.—Mix. 1-2 oz. of strong sulphuric acid with 1 oz. of 
strong nitric acid, and pour the mixture into oil of turpentine. The tur¬ 
pentine will burst into a flame. 

(4.) Decompositions by Galvanism. Color sulphate of potash solution 
with litmus. Pour this solution into a large glass bowl or vase, and fill 
two large tubes with the same solution. Invert the tubes in the bowl, 
and underneath introduce the electrode* ** rising a considerable height 
within the tubes. A change of color will soon appear. The solution in 


* Greek electron and odos (the path of the electricity), applied to the termination 

of the wires, or the poles and the wire near the pole. 





EXPERIMENTS. 


311 


the tube containing the positive electrode, will become red, that in the 
°il become deep blue. The electrodes in this experiment 

should terminate in long strips of platinum foil. To vary the experi¬ 
ment take a single narrow glass jar, of very wide tube, and within this 
insert both of the electrodes. The part of the solution towards the posi- 
tive electrode will become red, while that towards the negative electrode 
will be deep blue. This result is produced by the decomposition of the 
sulphate of potash which contains an acid (sulphuric), united to an alkali 
(potash). When decomposed the acid goes to the positive electrode and 
colors the solution of litmus around that electrode red, while the alkali 
goes to the negative electrode, and that portion of the solution therefore 
becomes blue. To vary this experiment still farther, use cabbage liquor 
instead of litmus solution with the sulphate'of potash ; also connect the 
two vessels containing the solution with lamp-wick or fine asbestos, and 
place one electrode in one vessel, and the other electrode in the other 
vessel. The different colors in this case will appear in the different ves¬ 
sels, for the acid and alkali of the solution will pass through the asbes¬ 
tos, the first to the vessel containing the positive electrode, and the sec¬ 
ond to the vessel containing the negative electrode.—Add hydrochloric 
acid to a solution of sulphate of indigo. In this solution place the elec¬ 
trodes while the battery is in action. The hydrochloric acid will be de¬ 
composed in the solution. Its chlorine set free will bleach (138.) the sul¬ 
phate of indigo.—Add iodate of potassa to a solution of starch. Place 
the electrode in the solution, and the iodate of potassa will be decom¬ 
posed. Its iodine set free will color the starch blue (141.) If hydro¬ 
chloric acid be now added, and the galvanic action continued, the acid 
will be decomposed, and the chlorine set free will bleach the blue iodide 
of starch in the solution.—Prepare a paper by covering it with a solu¬ 
tion of starch, to which iodate of potassa has been added. While the 
paper is still moist, place the point of one of the electrodes upon it and 
draw the point of the other over it. This last point will make a blue 
line wherever it crosses the paper, for, in this line, the iodate of potassa 
will be decomposed by the galvanic current, and the free iodine will 
color the starch with which it is in contact. In this manner, blue letters 
and blue writing may be formed with the metallic point of the elec¬ 
trode. A solution of litmus reddened by hydrochloric acid may be 
bleached , by placing the electrodes in the solution. Were it not for the 
bleaching property of the chlorine, the decomposition of the hydrochloric 
acid would restore the litmus solution to its original blue color. 

Electrotype decompositions; sulphate of copper, with the deposition 
of the metal upon any bright metallic surface, also nitrate of silver, 
acetate of lead, muriate of tin. Most other salts of these metals will 
act equally well. Silvering is ordinarily accomplished by means of a 
solution of the double cyanide of silver and potassium. For gilding , a 
similar solution of the double cyanide of gold and potassium is used. A 
solution of sulphuret of gold in sulphuret of potassium is also recom¬ 
mended. A strong solution of caustic potash may be decomposed, and 
the metal potassium (203.) precipitated. For this purpose, pour a thin 
stratum of mercury into a small glass vessel, having a flat bottom, and 
add a strong solution of caustic potash above the mercury. Connect an 
iron wire from the negative pole of the battery with the mercury, and a 
platinum wire from the positive pole with the potash solution. The 
potash will be rapidly decomposed, and the precipitated metal will 
unite with the mercury, forming an amalgam. The amalgam thus formed 
has the property of dissolving all the other metals. If a concentrated 


312 


ELEMENTS OF CHEMISTRY. 


solution of sal ammoniac be used instead of the caustic potash, an amal¬ 
gam of mercury and ammonium is formed. In forming this amalgam the 
mercury expands greatly in volume.—The two last experiments may be 
performed more easily by placing a piece of moistened caustic potash, 
or sal ammoniac, on a platinum plate which is connected with the nega¬ 
tive pole of the battery. Upon the potash, or sal ammoniac, is placed a 
globule of mercury. When the circuit is completed the amalgam is 
rapidly formed. 

(5.) Few experiments can be performed in electro-magnetism without 
a battery of considerable power. Among those more easily performed 
are the following: A wire is rendered magnetic by the galvanic current. 
Connect the poles of the battery by a wire and it will support iron fil¬ 
ings, &g. —If the current passes from north to south over a magnetic 
needle, this will turn at right angles to the wire, and point east and 
west. The north pole in this case always points east.—If the needle is 
placed below the wire while the current is passing from north to south, 
the north pole will move towards the west.—By reversing the direction 
of the galvanic current the position of the needle will be reversed.— 
These experiments may be still farther varied by passing the galvanic 
current vertically either upwards or downwards.—By making and break¬ 
ing the contact of the wire with*one pole of the battery, and, consequent¬ 
ly, making and breaking the galvanic circuit while the needle is near the 
wire, it may be made to oscillate, and, if the current be sufficiently 
strong, to revolve the eutire circuit.—( Olmsted’s Natural Philosophy , 
p. 306.) 

(6.) Into melted rosin one part put three parts of lard; the two will 
unite and form a compound that is more fluid than either of the constitu¬ 
ents. Other examples of affinity between bodies of a different nature 
are salt and snow, snow and sulphuric acid, the metals and the acids. 

(7.) Hence similar bodies, as the acids, expel each other to unite with 
the bases (see note, p. 95), which are entirely opposite in properties to 
acids. Hydrocyanic acid is expelled from its combination with baryta 
by carbonic, carbonic by nitrous, nitrous by sulphurous, sulphurous by 
boracic, boracic by acetic, and so on in the following order, benzoic, 
citric, arsenic, hydrochloric, nitric, phosphoric, oxalic, sulphuric, which 
expels all the others from their combinations with baryta. For all other 
bases a similar succession of affinities by the acids exists, while but few 
of the bases unite with each other. 

(8.) To 1-2 oz. sulphate of soda add 1-2 oz. nitrate of ammonia ; no ac¬ 
tion will take place till they are rubbed together in a mortar, when they 
combine and the compound is fluid. To 1-2 oz. sulphate of soda add 
1-2 oz. sulphate of zinc and 1-2 oz. acetate of lead. The same effect will 
take place as in the last mixture when these are rubbed together. Solu¬ 
tion produces chemical action for a sim^ar reason. Soda powders re¬ 
main weeks without action unless water be added. Fusion has, in many 
cases, the same effect. Ice and soda will not act on each other. Silica 
or sand and soda will not act. But melt the ice or the silica, and the 
soda will dissolve in the fused mass. Potash and sulphur will not unite 
until melted together, but after this, the fused mass will dissolve in 
water without separation, while, before fusion, the potash would dis¬ 
solve, and the sulphur remain undissolved. The potash and sulphur 
may also be united by rubbing together in a mortar (Expt. 3). 

(9.) As ammonia and cyanogen are each composed of two elements, 
their salts contain four elements, as the sulphate of ammonia, which 
contains sulphur, oxygen, and ammonia (nitrogen and hydrogen), and 


EXPERIMENTS. 


313 


the eyanate of potash, which is composed of potash, oxygen, and cyano¬ 
gen (carbon and nitrogen). In the double salts (246, and Expt. 66) the 
number of constituents is often more than four. A third compound will 
sometimes increase the affinity of two others, to which it may be added. 
Thus water will dissolve more quicklime when sugar is added than it 
will without the sugar. 

(10.) The compound of gold and lead is exceedingly brittle, though 
these metals are malleable, and the first the most malleable of all the 
metals (308.) Tin and iron form a very brittle alloy, though these 
metals, separately, are both malleable and ductile. So platinum and 
lead, two soft metals (when pure), form an exceedingly hard compound. 
All the compounds of platinum with the soft metals are quite hard. 
The least alloy of platinum produces this effect; hence, the hardness 
of ordinary platinum.—Pour a colorless solution of ammonia upon white 
calomel, the color is changed to a dense black.—Almost all the salts 
(p. 90) of the metals are entirely different from the metals, both in their 
appearance and properties. Sulphate of copper, chromate of potash, 
the salts of mercury and iron, are examples. 

(11.) Iron takes away acid from copper; hence, when a polished knife 
blade is plunged into a solution of a copper salt, the iron is dissolved, 
and metallic copper precipitated, which soon covers the knife with a 
coating of copper. Water takes alcohol from a solution of camphor ; 
therefore, when water is added to this solution, the camphor is precipi¬ 
tated. 

Drop a little aqua ammonia into a solution of sulphate of iron. The 
sulphuric acid of the sulphate of iron will leave the metal to unite with 
the ammonia. Sulphate of ammonia will be formed, and oxide of iron 
be precipitated. 

(12.) Nitrogen and oxygen in one proportion form nitrous oxide. 
When the oxygen is doubled, they form nitric oxide, which is the next 
compound above nitrous oxide. The next compound, hyponitrous acid, 
contains three proportions of oxygen. Four proportions of oxygen with 
one of nitrogen, form nitrous acid, and five proportions nitric acid. 

Success in obtaining the greatest amount of oxygen from the smallest 
guantity of material, without injury to the apparatus employed, requires 
attention to quite a number of points, which will also be useful in a 
great variety of chemical manipulations. 1 . The lamp. In the figure 
this is represented as it should be, a small sized lamp, the common alco¬ 
hol lamp of the laboratory. This is much better than a larger and more 
powerful lamp, whatever be the amount of oxygen required. 2. The 
stand. Any stand will answer that will hold firmly the flask or other 
vessels containing the chlorate of potash and manganese. The stand rep¬ 
resented in fig. 123, would answer best for this purpose. Avoid a sand 
bath beneath the flash 3. The vessel. A glass flask is the best suited 
for this purpose,—better than a copper retort which requires a higher 
heat and does not allow it to be as easily regulated. The flask should 
be at first about an inch above the point of the alcohol flame, and the 
wick of the lamp should be quite low, for the first portions of the oxy¬ 
gen are given off with great facility. The main object of the experi¬ 
ments is to keep a uniform flow of gas throughout the entire process. 
This is done by commencing with a very moderate heat. As the stream 
of gas begins to decline in energy the lamp is raised upon thm wooden 
blocks or circles, and the rapidity with which the gas is evolved in¬ 
creases. As it begins again to moderate the wick is pulled up, and af¬ 
terwards the heat is increased by placing one end of a slip of paper 

14 


314 


ELEMENTS *t)F CHEMISTRY. 


Fig. 110. 


about 18 inches long and from 8 to 4 inches wide, doubled throughout 
its length, in the flame of the lamp. (A newspaper or two should be 
previously cut up into these slips. The golden rule of the experimenter 
should be always to have , as far as possible, everything needed in a pro¬ 
cess at hand and in readiness before commencing the process) By con¬ 
ducting the process in this way the inconvenience and expense arising 
from the fusion of the flask will be avoided, much more gas will be ob¬ 
tained from the same materials than by any other method, and the 
whole process will be constantly under perfect control. 4. The cork. 
This is to be bored for inserting a tube preferably by cork borers , and 
if these are not to be had, by a red hot iron a little smaller thau the 
tube. In boring with an iron the cork should not be allowed to blaze, 
but this should be prevented if necessary by blowing upon it. 5. The 
tube. This should be of small size for ease in bending. The art of bend¬ 
ing a glass tube consists, (1.) in heating a considerable length, and not 
one point merely; (2.) in heating it so that it will require but a very 
slight pressure to bend it, and not to that degree when it falls of itself. 
If it falls of itself, or is bent with considerable pressure, in either case 
it will almost surely b z flattened. A tube well bent has a uniform curve, 
and the same capacity in the curve as in any other part. It will be found 
convenient to have a small additional piece of tubing, as represented in 
figure 110. 

(13.) In this figure c is an India-rubber connect¬ 
or tied at its two extremities to both tubes. Every 
laboratory should have some of these connectors, 
but they may be easily made out of sheet India- 
rubber, by wrapping a piece loosely around a 
tube of the size required, and cutting off the 
edges with a pair of scissors. The new cut edges 
unite throughout their length, and form a per¬ 
fectly air-tight tube. It is generally better before removing the connect¬ 
or thus made from the tube, to press the cut surfaces closely together 
without touching them. When the tube is thus prepared and fitted into 
the cork, the materials for oxygen are put into the flask, and the cork 
fitted in air-tight by means of thick flour paste,— not wax or cement , 
which would melt, and not only allow the gas to escape, but running 
down into the fused chlorate of potash, would produce a combustion 
more or less vivid in proportion to the quantity. 6. The material. The 
chlorate of potash should be coarsely powdered in a mortar with man¬ 
ganese, by which the two substances will be more thoroughly mixed, and 
the flow of gas, when heat is applied thoroughly, will be more regular, free, 
and abundant. The material thus prepared is introduced into the flask 
by a paper funnel. These funnels are of great service in the laboratory, 
and should be kept constantly on hand. The process of making them is 
so simple, and so easily learned by trial, that a full description is un¬ 
necessary. The following suggestions may be of some assistance: A 
dozen or more pieces of paper about 10 inches by 7, are cut. On the 
middle of one of the longer sides, which is to form the point of the cone 
or funnel, the finger is placed, and the remainder of the paper is rolled 
up around the hand in the form of a cone. Having by trial obtained 
the proper form, and observed the side or angle of the paper which re¬ 
quires paste, allow the paper to unroll, apply the paste, and roll it up 
again as before. If the paste is not too thick, the paper will at once 
assume and retain the form of a funnel. By a little practice a dozen or 
fifteen of these funnels may be made in as many minutes, when they 



EXPERIMENTS. 


315 


may be inverted over bottles or other supports to dry. When dry, they 
are stowed away one over the other, so as to occupy but very little 
room, and the points of the funnels are cut off as they are wanted for 
use. *7. The cistern. Where large quantities of gas are to be kept on 
hand, a cistern like that represented in p. 122, may be constructed. But 
as all the gas which is generally needed may be preserved in jars and 
bottles, the simplest and one of the most convenient forms is made out 
of water-tight box, or one made so by being lined with sheet lead 
soldered at the angles of the box. This box may be about 4 feet long, 
18 to 24 inches deep, and 2 feet wide. Into one side of this invert a 
box which is not water-tight. The last should reach within one or two 
inches of the top of the first, so as always to be covered with water. It 
should be of a breadth and width sufficient to hold (as a shelf) all the jars 
which will be needed. When the jars are to be filled with gas, they 
are brought over the edge of this box or shelf, and when full they are 
removed back and others brought forward. 8. Additional remarks. 
Before saving the oxygen which comes over , it should be tested by ap¬ 
plying a taper or a lamplighter , with a little fire upon the wick or paper, 
to a small jar or bottle of the gas. If the taper or lamplighter is rekin¬ 
dled into a blaze, the gas is sufficiently pure to save.—Much money is 
unnecessarily expended on large apparatus. Even a large lamp, in ex¬ 
periments on general chemistry, is not absolutely essential, for with the 
common lamp, and charcoal fires of greater or less intensity, and various 
forms, almost or quite all that is required may be done. To bend a 
glass tube, for example, put a few bricks on a hearth-stone, and be¬ 
tween them a few pieces of ignited charcoal; if necessary, add now and 
then a pine splinter, and over this small charcoal fire, a tube may be 
very easily and very beautifully bent. 

(14.) What remains in the flask after cooling (this should be gradual) 
may be -dissolved out with water. The tube, b, should not be left in the 
water after the gas has ceased coming over, as the gas within the flask 
will contract when the lamp is withdrawn, and sometimes before, and 
this contraction will draw the water up the lube, b, into the flask, and 
produce an explosion. 

(45.) Two fine wires should be prepared, or two watch-springs. One 
of the wires or watch-springs should be made into a coil, by taking out 
the temper and winding it around a ruler, or a glass tube. The coil 
should be about half an inch in diameter. The other wire, or watch- 
spring, should be left straight. The match on the end should be made 
with considerable care, to insure success and the best effect. It may be 
made by winding around the end of the wire about six inches of coarse 
cotton thread, so as to form a little ball. This ball is then dipped into 
sulphur. Before introducing the wire into the jar of oxygen, as much 
of the sulphur should be allowed to burn off as possible. This will heat 
the end of the wire to the requisite temperature, and the waste of oxy¬ 
gen in the consumption of a large amount of sulphur will be avoided. 

The following experiments may be tried, to illustrate some of the 
most important properties of oxygen:—1. Effect on a candle introduced 
into ajar of oxygen. 2. If the candle has a large wick (as that of a tal¬ 
low candle), which remains ignited after being blown out, it may be re¬ 
lighted in oxygen, and this experiment may be repeated a great number 
of times with a small jar of oxygen. 3. Through the centre of a lighted 
Argand lamp introduce a tube conveying oxygen gas. By admitting 
and interrupting the gas, a most splendid illumination will be produced. 
4 . Show sp. gr. of' oxygen by pouring it out on an extinguished taper 


316 


ELEMENTS OF CHEMISTRY. 


or lamplighter. 5. Burn a piece of phosphorus about the size of a pea in 
oxygen gas. 6. Burn caoutchouc in oxygen;—do. sulphur, camphor, 
charcoal, (a piece about an inch long, and of the usual size of wooden 
lead-pencils,) potassium, red fire (Expt. 2). To hold these bodies take a 
very narrow strip of stiff sheet iron, and bend up about an inch from’ 
the end, 60 that the extremity will spring against the part above, and, 
by its pressure, hold the object firmly. The iron strip may easily be at¬ 
tached to the cork by heating the unbent end red hot and burning it 
into the cork (without allowing the latter to blaze), and afterwards 
crowding in some paper which may be saturated with flour paste. Some 
of these substances require a deflagrating spoon (Fig. 128). This spoon 
should not be too deep. 

An India-rubber bag may be used to produce a jet of oxygen gas, and 
by this jet, a variety of beautiful experiments may be performed. It 
may be used with or without the flame of a spirit lamp, according to the 
experiment to be performed. When the object is supported on char¬ 
coal, a lamplighter is often preferable to a spirit lamp to commence the 
combustiou, after which it is continued by the charcoal and the body 
experimented upon. To use this jet, in a small cavity made in the char¬ 
coal support (by boring with a large screw driver or small chisel), or 
better with a coarse wire, somewhat larger than the average size of 
wooden lead-pencils, flattened at one end to a blunt or round edge about 
1-2 inch across, and with a cork or some other handle attached, which 
will be found of frequent use, introduce the following substances:— 
nitrate of strontia, nitrate of copper, boracic acid, amber, alum, sulphuret 
of lead (which is first reduced, and the metallic lead afterwards burns), 
acetate of zinc, metallic zinc, metallic copper, sulphuret of iron ; watch- 
springs broken up fine and introduced into a deep cavity of the charcoal, 
and covered with a little lamp-black,—which are first heated red hot, and 
then fly off in a shower of brilliant sparks,—iron filings prepared in the 
same way as the watch-springs, carbonate of soda, antimony or one of 
its salts, oxides of silver and gold (which are reduced to fulguration). 
Several of these metals, when reduced from their salts on the charcoal, 
may be thrown out on an inclined board, when they will divide into 
great numbers of small burning globules, which in rolling down the 
board will trace outlines of oxide formed in their combustion. 

The agency of oxygen in producing colors may be shown by a variety 
of experiments :—Damp faded silk, placed in a dry phial of oxygen gas, 
imbibes the gas, and in a few days is restored to its original brilliancy. 
This effect is, however, sometimes destroyed by the presence of certain 
mordants (245.) A solution of protoxide (protosulphate) of iron is at 
first of a light greenish tint, but by agitation absorbs oxygen from the 
air and becomes reddish-brown. Almost all the colors produced in the 
arts are manufactured from metallic oxides, and not only the intensity 
of the color, but also the kind depends, in a great measure, upon the 
degree of oxidation of the metallic base. In this way, from bodies 
which, with few exceptions, possess little beauty or color, the most 
beautiful and brilliant colors are obtained.—Light, by deoxidizing sub¬ 
stances, causes their colors to fade, although in other cases it darkens 
substances by producing decomposition. 

(16.) The action of oxygen in producing acids and alkalies, may be 
beautifully shown in the following manner:—Into two glass basins or 
vases, pour a solution of litmus, and upon a stand in one of the vases 
ignite a little sulphur. Over the burning sulphur, invert ajar (compare 
Fig. 35). The fumes of the burning sulphur within the jar will form 


EXPERIMENTS. 


317 


sulphurous acid, and this will be absorbed by the litmus solution beneath, 
the color of which will change to red. Into the other vase invert a nar¬ 
row cylinder, also full of litmus solution. Raise this cylinder slightly, 
and with tongs place underneath a globule of sodium. This being 
lighter than water will rise to the top of the cylinder, and will decom¬ 
pose the water, giving off hydrogen in the upper part of the cylinder. 
This will cause the litmus solution to descend, and, at the same time, 
the color will change (the litmus should have been previously reddened 
with the smallest possible quantity of acid) to a blue, from the formation 
of soda or oxide of sodium, by the combustion of the sodium, which, as 
it forms, is dissolved in the water. The same experiment may be tried 
with potassium, by placing it upon a stand in the vase, setting it on fire, 
and inverting over it a wide, empty jar. The litmus solution in the vase, 
if previously reddened, will turn blue. In the first case, therefore, an 
acid was formed by the union of sulphur with oxygen, and in the second 
case, an alkali by the union of sodium with oxygen. The experiment 
may be varied by using cabbage liquor instead of litmus solution. Po¬ 
tassium and sodium should never be placed in water without some degree of 
caution, as violent explosions have taken place on the first contact of these 
substances. To be prepared for such accidents, which cannot always be 
avoided, the experimenter should have at hand a pail, or bucket of 
clean water. In the above experiment, if an explosion should take 
place, some caustic potash or soda might be thrown in the face or eyes, 
and the immediate application of cold water would be the only resource. 
These explosions of potassium or sodium on first contact of water are, 
however, exceedingly rare. That oxygen itself is neither acid nor alka¬ 
line (although many of the gases are 141, 149, 151, 153, 154, 155), may 
be proved by suspending a piece of litmus paper from the stopper of a 
jar, and then filling the jar with oxygen. Blue litmus will not be color¬ 
ed red, and reddened litmus will not be tinged blue. 

(17.) The air within the jar at first expands by the heat; it must, there¬ 
fore, have a vent in which it can escape from beneath in such a manner 
as not to overturn the jar. This may be accomplished, by slightly ele¬ 
vating one side by placing a small support, as a piece of stick, under that 
side. A better method, where it can be adopted, is to use a stoppered 
Jar (see.“chemical apparatus,”) and to the opening attach a bladder. 
Press all the air out of the bladder before inverting the jar over the 
burning phosphorus. The air in this case will find sufficient room for 
expansion within the bladder, and none need escape from beneath. 

(18.) A taper which has been extinguished in a jar of nitrogen, may 
be relighted in a jar of oxygen, but this must be done so quickly that a 
spark of fire shall remain on the wick of the candle after this is with¬ 
drawn from the nitrogen. This experiment may be varied by using 
three jars, one of nitrogen, another of oxygen, and a third of common 
air. In the first the candle will be put out, in the second relighted, and 
in the third it will burn as usual. 

(19.) Nitrogen may be prepared from animal fibre in the following 
manner:—Wash a piece of beef well, and cut it into small pieces; put 
these into a retort, and pour some diluted nitric acid upon them. Ap¬ 
ply the heat of a lamp, and insert the beak of the retort under a receiv¬ 
er. Nitrogen gas will come over and fill the jar. This is one of the 
best methods of preparing nitrogen. 

(20.) One of the most important points in chemical manipulation, is 
to make tight junctions. We would suggest the following as that which 
we have found best:—Thrust the end of the retort into the gun-barrel, 


318 


ELEMENTS OF CHEMISTRY. 


and fill up the space between with potters’ clay. Add enough clay to 
cover entirely the interval between the gun-barrel and the retort, so 
that a strip of doth will lie evenly over the whole junction. Then pre¬ 
pare some strips of cotton or linen, an inch or two wide and about two 
feet long, rubbing moist clay over them. When they are well saturated 
with clay and covered with a thin, smooth stratum, wind one of them 
around the clay at the junction, and bind down the whole with a cord 
of several feet in length. One strip of cloth may be sufficient, but it is 
generally best to use several. Before winding the cord over the central 
part of the junction, bind down with cord the two ends. This will keep 
the clay from spreading, and cause the subsequent winding to bind it 
into one compact and firm mass. In some cases, as where watery vapor 
is to pass through the tube, white lead may be used instead of, or to¬ 
gether with potters’ clay. 

The analysis of water is continually performed in vegetation. All 
vegetables have this power, and thus are formed, by the hydrogen of 
the water and the elements within the plant, oils, wax, gum, resins, sugar, 
&c., while the oxygen is given out by the leaves. 

(21.) It is not essential that the necks of the retorts should pass 
through the jar, for the combined gases, or the watery vapor produced 
by their union, being heated, will rise. The experiment may, therefore, 
be performed by lighting the hydrogen in the open air after it has 
blown off the common air from within the retort. Apply the lamp 
to the other retort to drive off the oxygen, and bring the jar, a, (with 
the platinum suspended from the cork and reaching a little .distance be¬ 
low the jar) above the stream of the mixed gases, so that these shall 
strike on the platinum sponge. 

(22.) The pieces of zinc should be about an inch square, if cut out of 
sheet zinc; if made from block zinc, they should be granulated. For 
this purpose, melt the zinc in a crucible and pour it ouf slowly into a 
pail of water. The zinc will congeal in small masses, or fragments, 
which may be obtained of any size desired, by pouring faster, or slower, 
into hot or cold water. The acid solution should contain about 10 parts 
of water to 1 of acid. The hydrogen from the flask should be tested 
before being saved, with a smalt test-jar , by which it may be determined 
whether it has ceased to be explosive. The zinc, whether block .or sheet, 
should not be too pure, for, in this ease, the evolution of hydrogen is too 
slow. With zinc less pure the evolution is more rapid by galvanic 
action. 

Pour some strong sulphuric acid on a few pieces of zinc. The ac¬ 
tion which may at first take place will soon subside. How add more 
water, the action will commence again, and thus it may be renewed 
several times, by adding a little water each time. Any other metal be¬ 
sides zinc, that is easily oxidized, or that will easily withdraw oxygen 
from water, will produce hydrogen. Any other acid which will dis¬ 
solve oxide of zinc, may be used instead of sulphuric acid. 

(23.) Since anhydrous sulphuric acid (S 03) contains no hydrogen 
(H), therefore, none can be evolved when metallic zinc (Zn) is added, 
and monohydrated sulphuric acid (S 03, H 0) retains its hydrogen (H), 
or its water. (H 0) with so much force that t his is not overcome by the 
decomposing force of the zinc. But when more water is added, this is 
decomposed by the metal, and the resulting oxide of zinc is dissolved in 
the hydrated sulphuric acid. On account of the lightness of hydrogen, 
a bell rung in this gas will hardly be audible. The bell may be sus¬ 
pended on a frame about the height of a jar, and a string attached which 


EXPERIMENTS. 


319 


shall reach beneath the jar. Cover the bell with the jar, and introduce 
hydrogen from the gasometer, or from a flask; if the bell is rung, its 
tone will continue to grow fainter as the jar fills with hydrogen, until it 
is scarcely audible. 

(24.) For the purpose of inhalation, hydrogen may be, in a great de¬ 
gree, purified by passing it through an alkaline solution. (See arrange¬ 
ment for washing gas in “chemical apparatus.”) Or use a common jar 
with a bent tube, as represented in the figure (this arrangement may 
answer all the purposes of a transfer jar, where the latter is not to be 
had). Inhale the gas over the cistern so that the water will rise in 
the jar, and will again fall when the gas is exhaled, Fill an India-rub¬ 
ber bag with the gas, or fill the transfer jar (see “chemical apparatus”), 
and attach to the stop-cock of the jar an India-rubber tube. After three 
or four inhalations, attempt to speak before breathing the gas from the 
lungs. The effect on the voice will be manifest, but will soon disap¬ 
pear. It is unnecessary to breathe a great quantity of the gas. 

(25.) Soap-bubbles may be exceedingly improved by the addition of a 
very small quantity (1-100 part) of a thiek gum-arabic solution. The 
lightness of hydrogen may also be shown, by taking a bell-glass full 
of this gass and inverting it. With a taper the escaping gas may be 
lighted at some distance above the bell-glass. 

(26.) These tones are best made by a very small fame from a brass 
jet. Much depends on the form and size of the jet, which should be 
small 

(2'7.) We have generally performed this experiment with a large, 
broken tube, as the neck of a retort. The same arrangement may be 
used to perform another experiment. While the hydrogen is burning 
at the mouth of the bell-glass, introduce a small jet of oxygen from a 
bladder provided .with a stop-cock and gas-jet. This jet of oxygen will 
burn on the exterior in contact with hydrogen, and, therefore, present a 
luminous cone, like the common blow-pipe flame (175.) 

(Art. 112.) Soap-bubbles blown with the mixed gases explode violent¬ 
ly on the application of a flame. A basin blown full of these bubbles 
will explode with a terrible report. A bladder filled with the mixed 
gases may be exploded by piercing it witli a pointed wire heated red 
hot. A deafening explosion will ensue. This mixture may be exploded 
by the electrical spark, and the bladder may, therefore, be prepared 
with an interrupted circuit (as a broken wire, the parts separated about 
1-8 of an inch), by means of which, the mixed gases within may be ex¬ 
ploded. 

(Art. 115.) Pure water in large masses is not perfectly colorless, but 
ff a splendid blue, as is seen in the lakes of melted snow among the 
Alps, and in the water of the Polar Seas. 

(28.) Water alone sometimes appears to act like the acids. Thus 
pure water first oxidizes lead, and then dissolves the oxide thus formed. 
When steam at a high temperature is passed over some of these salts, it 
ieeomposes them. Thus, under these circumstances, sulphate of lime 
s decomposed, and the sulphuric acid is either displaced by the water 
to combine with the lime), or united to the water by a superior affini- 
;y for that than for lime at this temperature aud in this form. Water 
lbs orbs the same volume of a given gas at every state of density. As 
he latter varies (1) with the pressure, water will absorb move of a gas 
is the pressure upon that gas is increased. As the density of gas varies 
2) with its temperature, water will absorb more gas at a low, than at 
i high temperature. The gas which has been absorbed at a low tern- 


320 


ELEMENTS OF CHEMISTRY. 


peratnre, and under increased pressure, will be given off when either of 
these conditions is removed. Hence, boiling water expels the gases 
which it contains, and renders it insipid to the taste, and incapable of 
supporting the life of animals, who breathe the oxygen which it con¬ 
tains, and thus live in this element. Removing the atmospheric press¬ 
ure from the surface of the water will produce the same effect. 

(29.) Cold water takes up 1-750 of lime; hot water only. 1-1280. A 
pint of boiling water will dissolve 6 3-4 grains of lime, a pint of freez¬ 
ing water, 13 1-4 grains. Pour a little lime into cold water, and stir it 
up with the water for a short time, then allow it to settle, and pour off 
the clear liquid which contains lime in solution. Heat this solution to 
the boiling point; as it becomes hot it will deposit a portion of its lime, 
and this will be dissolved again as it cools. 

(Art., 116.) Ho manure, either mineral or vegetable, contributes to 
the growth of plants, until its constituents are rendered soluble in water. 
—Wheat contains 14-5 per cent, of water, rye 16‘6, oats 20'8, barley 
13-2, Indian corn 18, peas 16, beans 14-11, potatoes 75'9, turnips 92'5, 
carrots 87'6, beet-root 87*8, white cabbage 92*3, blood 80, muscle of 
beef 74, of veal 75, of mutton 71, of pork 76, of chicken 73, of trout 
80-5. 

(30.) The water evaporated by plants is perfectly pure; at least it 
does not contain 1-10,000,000 of foreign matter absorbed from the roots. 
Hence all the solid matter drawn up with water from the roots of 
plants, and all the gases with which that water was charged, are ab¬ 
sorbed by the plants, and contribute to their nourishment. From the 
leaves of plants vast quantities of pure water are evaporated. A sun¬ 
flower, 3 feet high, evaporated daily 20 oz. of water, a quantity 17 
times greater than that lost by insensible perspiration from an equal 
surface of the human body. For this reason, vines trained on the walls 
of a brick house often make the building exceedingly damp, and trees 
near houses have the same effect.—In freezing water separates all for¬ 
eign substances which may be present. Air and other gases are thus 
expelled. If ice melted under oil, or water which has been deprived 
of air or other gas, be heated, it will not boil until it reaches the tem¬ 
perature of 270°, when it will fly into vapor with explosive violence. 
All coloring matters are expelled by freezing; saline and alkaline solu¬ 
tions are deprived of their salts and alkalies, and acids are also perfect¬ 
ly expelled. Many of the lower orders of animals approach nearly to 
the fluid state. They appear like a soft, transparent jelly, which, by 
spontaneous decomposition after death, or by the application of heat, is 
resolved almost entirely into a watery fluid. Thus a medusa weighing 
26 or 30 pounds, will be reduced to only a few grains of solid matter. 

(31.) When the diamond is enclosed in iron, and exposed to an in¬ 
tense heat, it is dissipated, and the iron around it converted into steel.— 
Jewellers sometimes expose such diamonds as are foul to a strong heat 
under charcoal to render them clear.—Charcoal may be pressed till it is 
as hard as a diamond.—Fine plumbago is said to be too soft to enable 
au artist to make a fine line. To produce this effect a hard resinous 
matter is intimately combined with the lead, as follows : Fine Cumber¬ 
land lead and shell-lac are first melted together by a gentle heat. The 
compound thus formed is reduced to powder and re-melted until both 
substances are perfectly incorporated. This mass is afterwards sawed 
into slips, and glued into cedar mountings. To render the pencils of 
various degrees of hardness, the materials are differently proportioned, 
the hardest having the most shell-lac, the softer very little, and the 



EXPERIMENTS. 


321 


softest none. The blackness is in proportion to the softness. The cheap¬ 
est kind are made of powdered black-lead and sulphur. When held in 
the flame of a lamp they will soften in proportion to the sulphur which 
they contain. 

(32.) A slip of wood set on fire, and held with a pair of pinchers in a 
test tube until the volatile portions of the wood have passed off in 
flame, will illustrate the process of making charcoal.—Strong acids take 
a portion of the oxygen and hydrogen from wood, and therefore leave 
the carbon, or carbonize the wood. Heat increases the action of these 
acids. If, therefore, writing is made on paper with common sulphuric 
acid, it will be invisible until heat is applied.—When recently made, 
charcoal is very apt to take fire, by the action of the oxygen of the air 
which it rapidly absorbs. 

(33.) The ancient Britons placed charred stakes in the bed of the 
Thames, to prevent the passage of Julius Cfesar and his army. These 
were found nearly a century since, with their heart-wood still solid and 
firm, and their forms preserved completely. The writings of the an¬ 
cients are still found at Herculaneum perfectly black. The basis of 
their ink was finely divided charcoal. When the stumps of trees are 
charred in burning land, they last much longer than they otherwise 
would. 

(34.) Recently ignited charcoal, absorbs 95 times its bulk of hydro¬ 
chloric acid, 90 do. of ammonia, 65 of sulphurous, 40 of nitrous acid, 
9-42 of carbonic acid, 9'25 of oxygen, 5 of carburetted hydrogen, 
1'75 of hydrogen. When agitated with water containing sulphur¬ 
etted hydrogen, it absorbs this gas and the water becomes inodorous. 
Clothes may be restored from any disagreeable odor which they may 
have acquired, by wrapping up in them, for a few hours, some pieces 
of animal charcoal. Animal charcoal will absorb even lime, when boiled 
with lime water. This property is not possessed by lamp-black or veg¬ 
etable charcoal.—Charcoal takes oxygen from nitric and sulphuric acids, 
being thus burnt and decomposing these acids. The charcoal should 
be well pulverized, and exposed to a red heat in a covered crucible. 
The crucible is removed from the furnace, and from a test tube (Fig. 
127) tied to a long stick, some strong nitric or sulphuric acid is dropped 
in upon the charcoal. A shower of sparks is produced, attended with 
sulphurous or nitrous acid fumes. 

(35.) Boil some brown sugar in water, and add to the boiling solution 
some powdered animal charcoal; continue the boiling, and the charcoal 
will absorb the color of the sugar. The same effect takes place when 
the colored solution is filtered through a bed of charcoal 2 feet in thick¬ 
ness. This charcoal may be conveniently placed in a tube or in the 
broken neck of a retort. Charcoal of charred blood is most efficacious. 
Wood charcoal has very little decolorizing power. A solution of sul¬ 
phate of indigo, filtered through a depth of 2 feet of animal charcoal, 
will pass out entirely colorless. Common vinegar boiled with charcoal 
powder is rendered colorless, Animal charcoal owes its remarkable 
decolorizing properties to the fact that its particles are insulated by the 
phosphate of lime of bone, and thus presented in the most favorable 
form for absorbing the coloring matters. 

(36.) Place a large wafer on a pin, or hold it with a pair of pinchers 
in the flame of a lamp till it takes fire, then remove it oyer a sheet of 
white paper. As it burns, the red oxide of lead (284.) is reduced by 
the charcoal of the wafer, and little globules of bright metallic lead fall 
out on the paper.—Mix 4 oz. of red lead with 1 oz. of charcoal powder 

14 * 


322 


elements of chemistry. 


in a crucible, and expose the mixture to a red heat for 1-4 of an hour, 
then pour out the contents of the crucible, and metallic lead 'will run 
from beneath the powder. 

(37.) See 258, 264, 267, 283, 291, 294, (sulphuret of silver in combina¬ 
tion with sulphuret of lead,) 302, 306. In Montserrat there is a moun¬ 
tain which in one part is covered with deposits of sulphur, derived 
from the decomposition of sulphur vapors which issue continually from 
fissures in the mountain, attended with great heat. Near these fissures 
respiration is impossible, and the metallic buttons of visitors are in¬ 
stantly tarnished. The sulphur mines of Sicily, the craters of volca¬ 
noes, and the Solfatera near Naples, are the chief sources of the sulphur 
of commerce. At Solfatera, the deposit, of sulphur occurs in a kind of 
sunken plain, surrounded by rocks, which is probably the crater of an 
ancient volcano. From this since the age of Pliny (A. D. 60), a consid¬ 
erable portion of the sulphur used in Europe has been obtained. 

(38.) The hot springs of Iceland deposit sulphur, and it is deposited 
by the sulphur springs of New York, Virginia, &c. From the moun¬ 
tain in Montserrat, mentioned above, there flows a rivulet, whose waters 
boil with violence and are charged with sulphur. New fissures are con¬ 
tinually formed in this mountain, while "the old ones are stopped up. 
About two miles distant, there is another similar mountain, with which 
this is said to have a subterranean communication.—Sulphur may be 
dissolved by boiling in 10 parts of spirits of turpentine. When the so¬ 
lution is cooled below 180° it deposits needle-shaped crystals. But the 
proper solvent of sulphur is sulphuret of carbon, of which 100 parts 
dissolve 73*46 parts of sulphur when hot, and 38*70 when cold. 

(39.) The sublimation of sulphur may be performed, by placing a 
small quantity on a hot brick or a hot piece of metal, and covering it 
with a large bell-glass. A broken bell-glass, or a large broken Leyden 
jar, if it is to be obtained, should be used, as it is somewhat difficult to 
remove the coating of sulphur from the interior.—Place a large tube, or 
broken neck of a retort, in a sand bath, and inclose a small portion of 
sulphur on a heated metal or brick within. Heap the sand around the 
bottom of the tube, to prevent the escape of sulphur fumes. The sul¬ 
phur will sublime and cover the interior of the tube. One of the best 
methods is to heat a little sulphur in a Florence flask. The sulphur 
crystalizes in beautiful yellow stars in the upper part of the flask. In 
a minute state of division sulphur may be shown by precipitating it 
from any of its solutions, as from the sulphuret of potassium or sulphu¬ 
ret of sodium by sulphuric or any other acid, or from sulphuretted hydro¬ 
gen by the peroxide of iron .—Fulminating powder —nitre 3, sulphur 1, 
dry carbonate of potash 2. If a few grains of this powder be placed 
upon a fire shovel over the fire, so that the powder shall heat very 
gradually, it will at first turn black, then fuse and emit a faint blue 
flame, and finally explode with a tremendous report. Sometimes the 
violence of the explosion is so great, that the shovel is indented. 

(40.) The combustion of phosphorus may be well exhibited by burn¬ 
ing a large piece on a tile or a piece of metal. If placed on woollen, 
lint, feathers, dry paper, or other bad conductors of heat, phosphorus 
will often pass from a state of slow to that of rapid combustion (97.) It 
inflames more readily when dusted over with a small quantity of pow¬ 
dered charcoal, or the flowers of sulphur. This spontaneous combustion 
of phosphorus, or even its oxidation, may be entirely prevented by the 
presence of a small quantity of olefiant gas, or ether vapor, or that of 
some essential oil. It may even be distilled in an atmosphere contain- 


EXPERIMENTS. 


323 


ing the vapor of turpentine in considerable quantity. Even in pure 
oxygen this slow oxidation does not go on, at least at a temperature of 
60°; but if this gas be ratified, or diluted with nitrogen, hydrogen or 
carbonic acid, oxidation commences. To show this, place a piece of 
phosphorus in a phial of oxygen and close the phial. After some hours, 
open the phial.and no fumes will arise. Now mix with the oxygen in 
the phial, a small quantity of either nitrogen, hydrogen, or carbonic 
acid, and set aside as before. On removing the stopper of the phial, 
phosphorescent fumes will be emitted. Place a bit of phosphorus be¬ 
tween two pieces of brown paper on a table, and pressing on one end of 
the paper, hold it firmly. Rub a cork over the phosphorus. When 
sufficiently rubbed, separate the papers, and the phosphorus will take 
fire and burn rapidly. This experiment illustrates the use of phospho¬ 
rus in matches, where by sudden condensation and friction so much heat 
is evolved that the matches take fire. To inflame phosphorus under 
water, put a few grains into a glass tumbler, and pour boiling water 
over it till the glass is half filled. Through a bent tube project a small 
stream of oxygen upon the phosphorus, and it will take fire under the 
water. The tube, in this case, should be of considerable length, as the 
phosphorus is frequently thrown out of the water by the violence of the 
action. The extremity should be drawn out to a point, to give a fine 
stream of oxygen. Phosphorus absorbs oxygen from the chlorate of 
potash (202.) with explosive energy. One of the most violent fulmina¬ 
ting powders is composed of chlorate of potash 1 grain, phosphorus 1-2 
grain. If a small portion of this mixture be struck on an anvil, a loud 
report will ensue, lodate of potash may be used instead of the chlorate 
in the following proportionslodate of potash 6 grs., phosphorus 3 
grs. Nitrate of bismuth may be used in the proportions, nitrate of bis¬ 
muth 4 grains, phosphorus 2 grains. This powder may be exploded by 
trituration in a mortar. With 2 grs. of phosphorus, either of the follow¬ 
ing substances forms a fulminating powder:—nitrate of silver 6 grains., 
nitrate of copper 12 grs., nitrate of mercury 4 grs., nitrate of potash 10 
grs. In these cases, the mixture should be wrapped in a paper, and 
struck with a hammer which has been heated in the fire. If a piece of 
phosphorus be pressed heavily on a small globule of potassium, a vivid 
combustion will ensue. In this case, both the phosphorus and the potass¬ 
ium burn by means of the oxygen of the air, the phosphorus being con¬ 
verted into phosphoric acid (152.) and the potassium into potash (19 1.) 
The phosphoric acid thus produced, unites with the base potash to torm 
phosphate of potash. Sodium may be used instead of potassium in this 
experiment, and the phosphate of soda will be produced, Chalk, which 
is carbonate of lime, may be decomposed by phosphorus, which takes 
the oxygen of the carbonic acid (153.) and leaves behind the carbon and 
the lime. For this purpose, the phosphorus is placed in a crucible, 
which is then filled up with chalk, so as to cover the phosphorus close¬ 
ly. The crucible is then covered with another crucible and subjected to 
a red heat in the fire. It is then removed from the fire, and, when cold, 
it will be found that the phosphorus has burnt with the oxygen derived 
from the carbonate of lime by which it was surrounded, and that this 
has become decomposed into carbon and lime. Phosphorus withdraws 
the oxvgen from nitrate of silver, and the metallic silver thus reduced, 
covers the phosphorus with a bright film. Phosphorus may be dissolv¬ 
ed in ether by boiling in a phial, or small flask, a grain of phosphorus 
in an ounce of ether. When a piece of cloth is wet with this solution 
and then exposed to the air, the ether evaporates, and a thin coating ot 


324 


ELEMENTS OE CHEMISTRY. 


phosphorus is left on the cloth. If the cloth is now immersed in a solu¬ 
tion of gold, the phosphorus withdraws the oxygen from the solution, 
and the gold thus reduced will coyer the cloth in every part. 

(41.) Insert a stick of phosphorus in a quill, and write on the wall; 
the letters will be luminous in the dark. In this, or in any other exper¬ 
iment with phosphorus, the phosphorus should not be handled except 
under water or with wet hands. If the phosphorus takes fire, it should 
be plunged under water or smothered in some other way, since it cannot 
burn without oxygen. A luminous mixture is made of lard 2 parts, rosin 
1 part; to the lard and rosin, when melted together, add some pieces 
of phosphorus, excluding the air immediately by covering the mixture, 
to prevent the combustion of the phosphorus. When the phosphorus is 
fully dissolved, the heat may be removed from the mixture, and the lat¬ 
ter be uncovered. It will continue to shine in the dark for a long time, 
and the heat evolved by the gradual combustion of the phosphorus will 
be so great as to keep the mixture in a melted state. Phosphoric ether 
prepared in a vial, as mentioned above, will phosphoresce whenever the 
phial is uncorked. Phosphoric oil (with olive oil) and phosphoric tur¬ 
pentine may be prepared in the same manner. 

(42.) Phosphorus, therefore, inflames at a temperature less than that 
of boiling water (212°), nitric acid (248°), turpentine (316°), sulphuric 
acid (620°), <fcc. Its action with these liquids at the boiling heat, is so 
violent that it cannot be inflamed on any of them with safety, except on 
water. It is inflamed on water at boiling heat, by placing it on a small, 
thin, glass capsule, or any body capable of floating on water and form¬ 
ing a support for the phosphorus which shall conduct heat to it. 

(43.) Phosphorus crystallizes in dodecahedrons. These crystals may 
be obtained from a hot saturated solution of phosphorus in naphtha, when 
this solution cools, and may be preserved in the naphtha. 

(Art. 136.) The flask for making chlorine should be larger, as the 
materials are very apt to froth. The mixture of acid and manganese 
should not more than one-fourth fill the flask. This should rest in a 
sand bath, covered with the thinnest possible stratum of sand. The 
sand baths sold at the apparatus shops are too deep for most purposes in 
general chemistry. We have been accustomed to make our own by un¬ 
soldering and throwing off' the rim of the tin covers which come on glass 
jars. (See Fig. 29.) The concave bottom of these covers, as well as 
the nature of the metal (tin), renders them the best adapted for sand 
baths. A deep sand bath full of sand accumulates, and also wastes a 
great amount of heat, and effectually prevents the supply of heat from 
being easily regulated. The previous preparation requires that the 
flask be put upon the sand bath, and the whole upon a lamp-stand or 
other support, at such a height from the table that a small alcohol lamp 
can be placed at some distance below the sand bath, and gradually rais¬ 
ed. It is not advisable to push the process so far as to require a high 
heat, for in this case chiefly hydrochloric acid will distil over. 

(44.) This color is best shown in a gallon jar or bottle full of the gas, 
which may be collected by the displacement of air. This color will be 
preserved for a long time if the'bottle is perfectly dry, and the gas may, 
therefore, be saved to contrast with iodine, nitrous oxide gas, <fcc. 

(45.) A little moist cotton placed around the gas tube where it enters 
the mouth of the bottle, will prevent the escape of chlorine by absorb¬ 
ing it, and will thus prevent the disagreeable effects which this gas pro¬ 
duces. 

(46.) Fill a quart bottle (of thin white glass) half full with chlorine 


EXPERIMENTS. 


325 


and the remainder with hydrogen. This may be done over water, but 
in a place -not exposed to the direct rays of the sun or to bright light. 
Place the bottle containing the mixture under a cover of wire gauze, 
and throw upon the gauze a beam of sun-light from a mirror. The hy¬ 
drogen and chlorine will unite with explosion, and burst the bottle with 
a loud report. The experiment may fail if the light is not thrown upon 
the bottle immediately after the mixture is made. It may be found 
more convenient to set the bottle in a covered box, which is then placed 
in the direct sunlight. Draw off the cover from the box by a string, 
and the mixture in the box will instantly explode. These gases should 
not be mingled in large quantity, as they sometimes explode without 
the direct light of the sun. Chlorine which has been prepared iu the 
dark has much less tendency to unite with hydrogen than that which is 
prepared in the light. By previous exposure to the sun its affinity for 
hydrogen is rendered still more active. 

(47.) The chlorine given off from chloride of lime in the upper part 
of a house, will soon descend and fill all the lower stories. This it does 
partly by its greater specific gravity than common air, and partly by 
the principle of diffusion of gases (193.) When chlorine water is cooled 
to 36°, dark yellow crystalline plates appear in it of the hydrate of 
chlorine, which are composed of 27‘7 chlorine, and 72 - 3 water. These 
crystals liquefy, and the gas flies off at 45°. 

(48.) A splendid combustion may be produced by lowering a globule 
of potassium in an iron spoon into a jar of chlorine. Chloride of potass¬ 
ium is produced. Chloride of sodium or common salt may be formed 
in the same way. A piece of thin paper wet with turpentine and fold¬ 
ed in the form of a match, will take fire instantly on being lowered into 
a jar of chlorine, and burn with a lurid flame and a very black smoke, 
^arising from the dense deposit of carbon. The paper match should be 
held with a pair of pinchers, and the excess of turpentine allowed to 
drop off before introducing it into the jar. Camphor, caoutchouc, 
ether, <fcc, continue to burn when inflamed and put into chlorine gas. A 
jet of chlorine will burn like a jet of oxygen in hydrogen gas (Expt. 27.) 
See latter part of Expt. 68. 

(49.) Chlorine in water (chlorine water) decomposes the water when 
placed in the sunshine, uniting with its hydrogen and giving off the 
oxygen. For this reason, dilute chlorine water promotes the germina¬ 
tion of seeds, as oxygen is the chief agent in producing and stimulating 
the germination of plants. Fill a small flask with chlorine water, and 
invert it in a vessel filled with water. If this is put away in a dark 
place, it remains unchanged; but if it is exposed to the sun, a colorless 
gas will collect in the upper part of the flask, in which a glowing taper 
will re light. This is therefore oxygen, which has been derived from 
the decomposition of the water by the chlorine. After some days the 
water will entirely lose its chlorine odor, and instead of bleaching 
litmus, will redden it. Chlorine water can be kept only in the dark, or 
iu a bottle covered with tin foil or with thick black paper. 

(50.) The cloth is first thoroughly washed, then boiled in lime water, 
and afterwards in caustic soda. This removes the resinous substances 
which may be upon the cloth. Thus cleaned, it is steeped in a solution 
of chloride of lime so dilute as just to taste distinctly, and finally it is 
thrown into very dilute sulphuric acid. This acid seizes the base lime, 
and chlorine is liberated throughout the substance of the cloth, which is 
immediately bleached. The operation is usually repeated, to ensure 
perfect whiteness, and the goods are then well washed in warm water. 


326 


ELEMENTS OF CHEMISTRY. 


White patterns are printed upon colored cloth by stamping the figures 
with tartaric acid thickened with gum water. The cloth is then im¬ 
mersed iu the chloride bath, when, on the parts to which the acid has 
been applied, the chlorine is liberated, while the remainder of the cloth 
remains unaltered. For experiment, cloths of a yellow color will be 
most easily bleached.—By itself, chlorine is too powerful an agent. It 
requires the quiescent or diluting effect of a combination with an alka¬ 
line base, potash or lime. Pour chlorine water into red wine or ink, and 
both liquids will lose their color. A nosegay of flowers, made damp by 
previously immersing them in water and shaking off the excess of wa¬ 
ter, will rapidly absorb chlorine and become bleached. If introduced 
in a dry state, they will be but little acted on by the chlorine. Pass a 
stream of chlorine from a small tube into a solution of litmus, indigo, or 
other vegetable infusion, and in a few minutes the color will be dis¬ 
charged. Pour one of these solutions through a funnel into a flask of 
chlorine gas. The color will be discharged as before. Litmus or indigo 
paper is bleached by chlorine. A simple bleaching solution is made by 
pouring a few grains of the chlorate of potash into a tea-spoonful of hy¬ 
drochloric acid. This is diluted with water, and substances soaked in it 
for a short time are bleached. Common writing is effaced when the 
paper or the writing is moistened and held in chlorine. 

(51.) It is soluble in *7,000 parts of water, but even this small quan¬ 
tity colors the water brown. Iodine vapor may be shown by volatiliz¬ 
ing a small portion in a large jar. similar to that employed for exhibit¬ 
ing the color of chlorine (Expt. 44.) The two jars, placed side by side, 
will form a fine contrast. The vapor may also be shown, by boiling a 
little iodine with a few ounces of water in a Florence flask; for although 
iodine vapor is seen to great advantage when a scruple or two of iodine 
is thrown on a hot plate or brick. When perfectly dry, iodine does not 
fuse below 225 p , and does not boil below 34*7°, yet when moisture is 
present, it is sublimed rapidly even below the temperature of boiling 
water. 

(52.) A lighted taper introduced into the jar of iodine vapor (Expt. 
51.) shows a retarded combustion, but a piece of phosphorus introduced 
on the deflagrating spoon takes fire and burns. Iodine thrown on phos¬ 
phorus in thin slices, will combine with the phosphorus. Heat will be 
extricated, and, if the bodies are in contact with air or oxygen, the phos¬ 
phorus will be inflamed. Three or four thin slices of phosphorus should 
be employed, and be previously dried with bibulous paper. (Art. 138.) 
Boracic acid, at a high temperature, has a property similar to that of 
water at a lower temperature—that of dissolving metallic oxides, and, 
on volatilizing, leaving them in a crystalline form, as water on evapor¬ 
ating leaves the salts which it holds in solution in the form of crystals. 
This property has been made use of to obtain many new and beautiful 
combinations, and enables us to imitate several crystals hitherto obtain¬ 
ed only from rocks. 

(53.) A large vase of cabbage liquor is turned red by a drop or two 
of sulphuric acid. (Stir the acid in the solution with a glass rod.) Add 
a small quantity of alkali, as. potash or ammonia, the original colors 
will be restored, and by adding more, a deep green will be produced. 
By a second addition of acid the solution can be again reddened, and 
thus the change of colors produced a great number of times. One grain 
of oxalic acid (329.) dissolved in three gallons of water, will reddeu lit¬ 
mus paper. Sulphuric acid diluted 35,000 times with water is detected 
in the same way. Among the vegetable blues which give the acid 


EXPERIMENTS. 


327 


and alkaline reaction, the following may be selected as examples; 
—blue morning glory, blue lily, trichostema dichotoma (blue curls,) 
petunia, dahlia, lady slipper, rose (red), miranda. Infusions maybe 
prepared of these flowers as directed for preparing cabbage liquor (see 
“ chemical processes,”) The noonsleep produces a fine red color with 
acids, but no alkaline reaction. The acid we employed in the foregoing 
experiments was oxalic acid, and the alkali a solution of carbonate of 
soda. Infusions of green leaves and stems of plants will usually show 
an alteration of color by acids and alkalies. The stain which acids give 
to cloth, may be removed by adding ammonia, if the latter be applied 
before the fibre of the cloth is destroyed. If the ammonia is added in 
excess no harm will be done, as this excess will soon evaporate, and 
leave The color of the cloth unaltered. v 

(54.) A definite relation exists between the acid and the quantity of 
base required to saturate it. 

100 oz. of sulph. acid take 118 oz. of potash, which contains 20 oz. oxygen! 

100 “ “ “ “ 70 “ of lime “ 20 “ “ 

100 “ “ “ “ 90 “ of protoxide of iron “ 20 “ “ 

100 “ “ “ “ 278 “ of oxide of lead “ 20 “ “ 

Every 100 ounces of sulphuric acid therefore take so much of any base 
as contains 20 oz. of oxygen. In the same way 100 pafts of nitric 
acid require for saturation 14 3-4 parts of oxygen in the base and 100 parts 
of carbonic acid, 36 1-4 of oxygen. A definite relation also,exists be¬ 
tween the oxygen of the acid to that of the base. Thus, 

100 oz. of S 03 contains 60 oz. of O, and the base contains 20 oz. of O 
(=1-3) 

100 oz. of N 05 contains 73 3-4 oz. of O, and the base contains 14 3-4 oz. 
of O (=1-5). 

100 oz. of C 02 contains 72 1-2 oz. of O, and the base contains 36 1-4 oz. 
of O (=1-2). 

Make a solution of nitrate of copper so weak as to be colorless. Add 
a little ammonia to this solution, and an intense blue color will be pro¬ 
duced. This color will be neutralized or destroyed by the addition of a 
little sulphuric acid. It may be again restored by the addition of more 
ammonia, and thus the color may be produced and destroyed a great 
number of times. 

(55.) Exp. 16 maybe repeated to illustrate the formation of acids and 
alkalies. 

(56.) Much the largest class of salts are those which are formed by 
the union of a metallic oxide with an acid. These salts are formed in 
the laboratory principally in three ways: (1.) By the action of the 

acid on the metal with the presence of water, or more strictly, the ac¬ 
tion of water on the metal with the presence of acid, by which the oxy¬ 
gen of the water unites with the metal, while the hydrogen escapes; 
(2.) A metallic oxide previously formed is taken for the base of the.re¬ 
quired salt; (3.) A carbonate is taken, the carbonic acid of which is 
more volatile , or a weaker acid than the one to be used in the formation 
of the salt. In one of these three methods (producing a metallic oxide) 
almost all the salts of the laboratory are formed. To caustic potash 
solution 1 oz. add sulphuric acid 1-2 oz. The compound formed by these 
two corrosive substances (sulphate of potash), is a mild salt possessing 
none of the properties of its components—To caustic soda 1 oz. add 
muriatic acid 1 oz. These corrosive substances form by their union com¬ 
mon salt.—Alum is an example of an acid combined with two bases, and 


328 


ELEMENTS OF CHEMISTRY. 


is therefore called a double salt (246.) Tartar emetic (330.) is another 
example. The acid (tartaric) is combined with two bases, antimony and 
potash. The nature of these salts may be illustrated as follows: Add 
potash to a solution of sulphate of copper, a simple salt sulphate of 
potash is formed, and the copper is precipitated. Instead of pure 
potash, add sulphate of potash to the sulphate of copper, and a double 
salt of sulphate of potash and copper is obtained. In the first case, 
where the potash was added to the sulphate of copper, the sulphuric 
acid was deficient for both bases—the copper and the potash; and there¬ 
fore it left the copper 'for the potash. But in the second case, where the 
sulphate of potash was added to the sulphate of copper, the acid was 
in the right quantity for both bases, and therefore the double sulphate 
of potash and copper was formed. The double salts are not mer & mix¬ 
tures of the simple salts, for the crystallization and properties of the 
double salts are, in many instances, different from those of the simple salts. 
The double salt may be a rhomboidal blue crystal, while one of the simple 
salts is a flat, prismatic, white crystal, and the other a green powder, <fcc. 

(57.) Suspend a rose, or a similar flower, in a jar of sulphurous acid 
gas, and it will be bleached. The color, however, will gradually return 
on exposure to the air, and it may be restored at once by plunging the 
rose in water.—Pass a stream of sulphurous acid gas through, or pour 
some sulphurous acid water into an infusion of logwood. The dark 
liquid will be immediately bleached. Add a few drops of sulphuric 
acid, and 'the color will be restored.—The fumes of burning sulphur 
quickly blacken silver, forming a sulphuret of silver. When a thick 
crust of this sulphuret is thus produced, it may be struck off from the 
silver by a heavy blow on an anvil, and the silver is left quite clean. 
By exposing to heat the sulphuret of silver thus obtained, the sulphur 
is driven off and the silver revived. This, therefore, is one of the meth¬ 
ods by which silver coins are sometimes robbed of a portion of their sil¬ 
ver. Wool is prepared for bleaching by plunging it into a hot solution 
of soap, which dissolves off a great quantity of greasy matter. The 
wool by this process often loses 70 per cent, of its weight. When thus 
cleansed, it is taken to the sulphur chamber, where it is exposed from 5 
to 20 hours, according to circumstances. It is then again washed, and 
immersed in a bath of pure whitening and blue. The process is com¬ 
pleted by a second exposure to the fumes of sulphur, and by washing it 
again in a solution of soap. 

(68.) The deadly character of sulphurous acid is seen in the common 
practice of destroying bees by the fumes of sulphur. A bundle of 
matches lighted, will effectually destroy all the bees of a hive, sometimes 
20,000 in number.—Insects for cabinets, are generally destroyed by the 
fumes of sulphur. The fumes of prussic acid (383.) are to be preferred, 
as sulphur sometimes injures the colors. (Art. 145.) If a chip moisten¬ 
ed with nitric acid be let down into a jar of sulphurous acid gas, it will 
be surrounded with reddish yellow fumes (nitrous acid), owing to the de¬ 
composition of the nitric acid, which yields a portion of its oxygen to 
the sulphurous acid, aud converts it into sulphuric acid. 

(59.) See Expt. 7. Sulphuric acid expels oxygen from the chlorate of 
potash (202.), and in this way may be made to set fire to a small quan¬ 
tity of alcohol. 

(60.) Dip a piece of sponge into water, and afterwards wring it out, 
and suspend it w hile still damp in the upper part of a bottle which holds a 
little strong sulphuric acid. The acid will attract the moisture from the 
sponge so rapidly, that it will soon become dry, while the acid will be 


EXPERIMENTS. 


329 


increased in bulk, in proportion to the quantity of water at first adher¬ 
ing to the sponge.—Into a saucer pour 3 oz. of sulphuric acid, and leave 
it exposed to a damp atmosphere for 24 hours. At the end of that time, 
the 3 oz. will have increased to nearly 4, on account of the moisture ab¬ 
sorbed from the atmosphere. 

(61.) A large jar of nitrous acid gas may be exhibited by putting a 
few grains of copper, silver, or tin, in the bottom of the jar, and pouring 
a little dilute nitric acid upon the metal. When the jar is full of nitrous 
gas, put a little wet tow, wool, or cotton over the mouth, and this will 
absorb the excess of gas, and prevent its escape into the room. The gas 
thus prepared will form a fine contrast with the bottle of chlorine 
(Expt. 44.) and that of iodine (Expt. 51.) 

(62.) Quills are sometimes dyed vellow. Dip a quill into nitric acid, 
and let it remain from a second to nve minutes according to the strength 
of the acid. No immediate effect will be perceived upon the quill, but, 
on taking it out and exposing it to the light, it will turn to a bright and 
very durable yellow. The quill should be washed in water after being 
taken out of the acid.—Woollen goods may be colored or marked in the 
same way. Any desirable pattern may be printed on a piece of flannel 
or colored cloth with dilute nitric acid, and a permanent yellow color 
will be imparted to the cloth. After a short time, the superfluous nitric 
acid should be washed away to prevent its corroding the cloth. 

(63.) If a piece of glowing charcoal be dropped upon the surface of 
strong nitric acid, the charcoal will burst into an intense flame. Cau¬ 
tion is required in this experiment lest the violence of the action scatter 
the nitric acid about. If phosphorus is thrown into strong and hot 
nitric acid, it burns with a splendid combustion. Very small quantities 
of phosphorus should be used, as the action is exceedingly violent, and 
the phosphorus is often thrown about in jets of fire. A tall and nar¬ 
row vessel is generally employed.—From a test tube tied to a long stick, 
pour a few drops of concentrated nitric acid on bismuth. A rapid com¬ 
bustion will take place, and nitrate of bismuth be formed. Tin, zinc, 
or red hot iron filings may be inflamed in like manner—(p. 98.) Com¬ 
mercial nitric and hydrochloric acids are sometimes so weak that they 
will not act readily on gold-leaf. In this case the addition of sulphuric 
acid concentrates the mixture of the other two acids by withdrawing 
water, and brings on immediate action.—One of the best tests for nitric 
acid is to heat gently the substance with pure sulphuric acid in a test- 
tube, and add, (from another test-tube, inclining both,) very cautiously, 
a solution of protosulphate of iron. At the time of junction of the two 
liquids, a dark band will be seen, produced by the action of nitric acid 
on the protosulphate of iron. By this action the P ar ^ n drie 

acid can be detected. A very good test for nitric acid in a solution is 
to add one or two drops of yellow prussiate of potash. To this splu- 
tion, which as yet is colorless, add one or two drops of acetic acid. If 
the liquid contains nitric acid it will immediately, or after standing, as 
sume a rich yellow tint.—Nitric acid of sp. gr. 1'485, has no more action 
upon tin than water has. But when it is either stronger or weaker, it 
oxidizes the tin with extreme energy.—Nitric acid may be formed by 
the passage of electricity through a confined portion of air. The forma¬ 
tion of the acid in this case is probably due to the oxidation of the nitro¬ 
gen of the atmosphere by ozone, which is always formed in these cir¬ 
cumstances. Ozonized air, in contact with lime-water, will, without 
electrical action, produce nitric acid, which combines with the lime to 
form nitrate of lime. 


330 


ELE1IEXTS OF CHEMISTRY. 


(64.) Carbonic acid may be poured from one vessel to another ; it 
will extinguish a light, or redden litmus solution in the second vessel. 
A light may also be extinguished by a stream of carbonic acid poured 
directly upon it,— Pass carbonic gas into a solution of litmus until it is 
reddened. Boil the solution thus reddened, and the blue color will re¬ 
turn, the carbonic acid being expelled by heat. 

(65.) Put a few grains of chalk in a tall glass jar, and pour upon it a 
teaspoonful of hydrochloric acid ; carbonic acid will be liberated, and 
will fill the jar. A lighted taper immersed in the jar is extinguished. 
An animal, as a mouse, is soon suffocated in the gas. — This gas exerts 
even a poisonous influence on life. A land tortoise was deprived of one 
lung by tying up its air tube, and yet supported life by the other for 
several days; but when one lung was made to breathe carbonic acid, 
while the other breathed pure air, tffe animal died in a few hours. An 
atmosphere containing one per cent, of carbonic acid is injurious, and 
requires immediate ventilation. Miners, however, gradually accustom 
themselves to an atmosphere containing an amount of carbonic acid that 
would destroy a person suddenly entering into it without such prepara¬ 
tion. But even with miners, frequent accidents occur, showing that 
habit does not secure them from the deadly influence of this gas. — In¬ 
sects may be destroyed by immersion in carbonic acid, and be preserved 
in a good condition for a cabinet, — Carbonic acid also exerts a positive 
influence in checking combustion. The flame of a candle is extinguished 
in an atmosphere containing only five or six per cent, of this gas. — 
Carbonic acid gas has been applied to the extinction of fires in coal 
mines, with great success. These fires may be extinguished in one or 
two days by this method, while by the old method of sealing up, flood¬ 
ing, and pumping out, great labor was required, and months, or even 
years of time expended. It has been proposed, also, to extinguish the 
fires in ships in the same way. Several vessels containing chalk or 
broken marble, are to be distributed through the lowest part of the ship, 
and near them other vessels of hydrochloric acid. The latter vessels 
are to be connected with the former by pipes closed with valves. 
Strong wires lead from these valves to the deck. As soon as the fire is 
discovered, all means of communication with the external air must be 
closed, and the valves opened by means of the wires. The vast amount 
of carbonic acid produced by the contact of the acid with the carbonate 
of lime, will soon displace the common air, fill the whole ship, and ex¬ 
tinguish the combustion. 

(66.) A white precipitate of carbonate of lime is produced in lime- 
water, by blowing into the water through a tube or pipe. The carbonic 
acid of the breath unites with the lime, and the compound being insolu¬ 
ble is precipitated. A precipitate of carbonate of baryta may be form¬ 
ed from baryta in the same way. The latter is a more delicate test 
for carbonic acid than the former, and will soon detect its presence in 
the air of the room where it is exposed. If a jar be held for some time over 
a charcoal furnace, and the bottom then covered with a glass plate and 
inverted, baryta or lime-water poured in will detect carbonic acid in 
large quantity, by an immediate and dense white precipitate. Into the 
milky liquid thus formed pass a stream of carbonic acid. It re-dissolves 
the carbonate of lime. Boil the solution thus rendered clear, and it 
again becomes milky. — The quantity of carbonic acid exhaled, is great¬ 
est from 11 A. M. to 1 P. M. ; smallest between 8 P. M. and 8 A. M. It is 
also greater when the barometer is low. By active exercise it is greatly 
increased. This difference is enormous in insects. Their respiration 


EXPERIMENTS. 


331 


when at rest is as feeble as that of cold-blooded animals; but when in 
active movement they consume more oxygen in proportion to their size 
than aniinals of any other class.—The amount of carbonic acid exhaled 
depends in a great measure on three circumstances: (1.) The amount of 
active exercise. (2,) The temperature of the body. (3.) The amount 
of carbonic acid in the air which is breathed. Thus 300 cub. in. of air 
respired three minutes, gave only 28 1-2 cub. in. of carbonic acid; 
while fresh air respired during the same time, gave 32 cub. in. The 
proper aeration of the blood is therefore destroyed whenever persons 
are confined where there is not sufficient ventilation.—Delicate analysis 
detects a slight difference between the air of a crowded city, and that 
near the luxuriant vegetation of the country in respect to carbonic acid. 
During sleep less carbonic acid is exhaled, probably on account of the 
cessation of muscular exertion, and on account of the warmth of the body. 
—Into a jar of carbonic acid standing over water put a few freshly- 
gathered cabbage leaves. Expose the jar to the direct rays of the sun. 
After three or four hours, oxygen will be found in the jar with the car¬ 
bonic acid. At night take a jar of oxygen standing over water, and put 
within a few fresh cabbage leaves. Oxygen will now be absorbed, and, 
after several hours, carbonic acid will be found in the jar with the oxy¬ 
gen.— Into a glass vessel filled with water put a sprig of a plant and a 
fish ; let the vessel be tightly corked, and placed in the sun. The plant 
will liberate oxygen. This will be breathed by the fish through the 
medium of the water, which in turn will give out carbonic acid to be 
decomposed by the plant. Remove the vessel from the sun-fight, the 
plant will cease to give out oxygen, and the fish soon languish ; but will 
revive when replaced in the light.—Water saturated with carbonic acid 
proves highly nutritive to plants when applied to their roots. Plants do 
not vegetate well in the sun if deprived of carbonic acid, nor well in the 
shade if carbonic acid in excess is present. — Saussure has demonstrated 
by experiment, that the increase of plants in weight is exactly propor¬ 
tioned to the amount of carbonic acid which they decompose, and the 
oxygen which they give off. Much the greater part of the carbon of 
plants is obtained in this way.—When daylight ceases, the plant becomes 
charged with carbonic acid, by absorption through the leaves and roots. 
Of this acid part escapes during the night with watery vapor from the 
leaves.— Recent calculations have shown that the atmosphere contains, 
in its carbonic acid, enough carbon to furnish through vegetable action 
about 850,000,000,000 tons of coal. The probable quantity of coal in 
the earth is nearly 5,000,000,000,000 tons, or about six times that which 
the present atmosphere could produce. Hence, the atmosphere in past 
ages must have contained six or seven times as much carbonic acid as 
it does at present.—The carbonic exhalations from the earth probably 
originate at a depth where the temperature is at least 212 , or about 
9,000 feet below the surface. At this temperature, in presence of water 
at boiling heat, silicic acid gradually separates carbonic acid from the 
carbonates of lime, magnesia, and iron. 

(67.) See Expt. 46. A better method for observing the union of these 
gases is to fill a tube 12 in. long, and 1-2 inch internal diameter with 
the mixed gases. Expose the tube to full fight. The combustion of the 
gases will be seen to commence almost instantly by the cloudy appear¬ 
ance produced within the tube. Now cover up the tube and the action 
will cease until the tube is a second time exposed. Thus by repeating 
the experiment, the action of the fight upon the gases is beautifully 


332 


ELEMENTS OF CHEMISTRY. 


shown, while from the small size of the tube there is no danger in sub 
mitting the whole to the direct rays of the sun. 

(68.) Wrap a jar or phial with a towel, and till it with the mixer 
gases, and quickly let fall within a lighted match. A loud explosioi 
will ensue. The jar will not burst if it has an open mouth, and is toler 
ably thick. After the explosion pour in a little solution of litmus, am 
it will be immediately turned red, showing the presence of an acid 
Into a similar jar of the mixed gases which have not been exploded, it 
a little litmus solution be poured, the color will be bleached by the frer 
chlorine. If after explosion the bottle be immediately turned moutl 
downwards into the pneumatic cistern, or a basin of water, the hydro ; 
chloric acid gas with which it is filled will be so rapidly absorbed by th< ; 
water, that the latter will rush up into the bottle until it is entirely 
filled with water. The jet of chlorine in hydrogen gas (Expt. 48), sooi 
ceases to burn on account of the formation of hydrochloric acid gas with 
in the jar or tube in which the jet is burned. j 

(69.) Provisions put up by a certain English house were for a lon^ 
time in great demand for ships trading to the Indies. They were mad 
to keep in a much better state of preservation during long voyages fr 
the addition of a little muriatic acid in each cask. A large fortune wa 
realized by the possession of this secret. , 

(70.) It may be used to remove blots from books and paper, as it rej 
moves the stains of common ink, but does not affect printer’s ink. It ij 
generally best to add 1 oz. of red lead to 8 oz. of muriatic acid wher 
used for this purpose. i 

(71.) Sulphuric acid takes the lead in the preparation of the othe 
acids; hydrochloric acid, as a solvent, rules in chemical analysis; am 
carbonic acid is pioneer in the preparation of salts; hydrosulphuri 
acid (sulphuretted hydrogen) is the great precipitant; nitric acid is th; 
most direct and the most powerful oxidizing agent. 

(72.) Although this gas is heavier than common air, yet bubble 
blown with a mixture of sulphuretted hydrogen 2-5, and oxygen 3-f 
will ascend. If lighted with a caudle, these bubbles will explode wit 
a loud report, forming water and sulphurous acid. Bubbles may also b ; 
formed with a mixture of sulphuretted hydrogen 3-5, and nitric oxid 
2-5. These bubbles explode and burn with a light green flame. If th 
gases in these proportions are mixed in a jar and inflamed, a greenish 
flame will pervade the whole jar.—Sulphuretted hydrogen acts as j 
poison by destroying the power of the blood to perform its functions. j 
(73.) Several different colored flames may be exhibited, by preparin 
bottles with tubes passing through their corks and drawn out above to . 
point. This is broken off so as to produce a very fine jet of gas. Int 
one of these bottles place the materials for hydrogen gas, into anothe 
the same materials with a few drops of turpentine or ether in the soli i 
tion, into a third the same materials with a little nitric acid, into a fourt 
the materials for sulphuretted hydrogen, and into a fifth the same mt j 
terials with a little nitric acid. All these will, when fired, produc- 
flames of different colors.—After all the sulphuretted hydrogen is coi 
lected which is desired, the remainder may be lighted as it issues froi 
the tube, and thus the color of the flame be exhibited, and the offensiv 
fumes avoided.—A jet of large size and great beauty may be formed b 
filling the gas bag with sulphuretted hydrogen and firing the jet as tb 
gas is driven out of the bag by pressure. 

(74.) Images drawn with acetate of lead will remain colorless, unt J 
a stream of this gas is made to fall upon the still moist surface. Tb 





EXPERIMENTS. 


333 



figures are then brought out of a deep black color (by the formation of 
mlphuret of lead); we have generally formed two figures, one a land¬ 
scape, the second a caricature. 

(75.) This gas forms a white precipitate with solution of the peroxide 
of iron, splendid yellow precipitates with cadmium, arsenic, and tin, 
splendid orange precipitates with antimony, brown with tin, black with 
lead, copper, bismuth, silver, gold, platinum, and, mercury. 

(76.) Ihe discoloration of silver spoons used with eggs is owing to the 
sulphur contained in the eggs. 

(77.) The vessel of lead should be about 6 inches long, 5 inches wide, 
ind 1 inch deep. The pieces of glass should be cut considerably smaller, 
and fitted to a wooden support, which is cut out in the centre (Fig. 111.), 
so that the glass rests upon it only on the corners, a , a, a, a. The 
wooden support should be somewhat larger than the leaden box, Fig. 111. 
and should rest upon this box at the corners. It may be cut in 
a few minutes out of the wood of a segar box. If the leaden 
vessel cannot be conveniently obtained, after the plate of glass 
is covered with wax and the figure drawn, surround it (the plate) 
with a raised edge of wax, and pour upon it dilute hydrofluoric 
acid. The fumes of the acid should be carefully avoided. The 
affect may also be produced by dusting the glass with some finely 
powdered fluor-spar, and adding a little sulphuric acid to disengage the 
gas from the fluor-spar. A part of the gas will fly off, and may be detected 
by placing a second piece of glass over the first, but another portion will be 
retained in the liquid, and this portion will corrode the glass beneath. In¬ 
stead of the lead vessel, a bowl may be used which has been rubbed 
with paper saturated with oil.—A thermometer tube, or a similar ob¬ 
ject, is marked by being coated with wax through which the required 
lines are traced. The whole is then dipped into sulphuric acid and 
afterwards dusted with fluor-spar in fine powder. 

[Art. 161.] Ebelmen, a French chemist, has lately succeeded in form¬ 
ing a number of artificial gems, by availing himself of the two proper¬ 
ties of boracic acid, of dissolving metallic oxides by fusion, and then vol¬ 
atilizing at a higher heat. His process for making ruby is as follows : 
After making a mixture of alumina and magnesia, in the same propor¬ 
tion as they exist in spinel, one-half to one per cent, bichromate of potash 
is added to this, and the whole mixed with half its weight of fused 
boracic acid, and exposed in platinum resting on porcelain to the heat of 
a porcelain furnace. A similar method is pursued for other gems. 

(78.) Silica also serves a very important purpose in the manufacture 
ff mortar. It gives strength to the mortar by interposing a hard sub¬ 
stance between the loose crystalline structure of the carbonate of lime. 
It also serves as nuclei for crystallization (like sticks in a saline solu¬ 
tion). Therefore the harder and sharper the sand is, the better it is 
suited for mortar. 

(79.) When seeds (of the Lepidium sativum) were sown in platinum 
wire cut fine in a platinum crucible, plants were produced which yield- 
3 d the same quantity of ash as a weight of seed equal to that which 
Was sown. But when seeds were sown in quartz-sand, which had pre¬ 
viously been treated with aqua-regia, the quautity of ash which the 
plant left was double that from the seed. In both cases the plants were 
protected from dust, and were moistened with distilled water. On the 
analysis of water which had been left for a month in contact with 
quartz-sand, and through which during this period a continual current 
of carbonic acid was passed , it was found to have dissolved out from the 



334 


ELEMENTS OF CHEMISTRY. 


quartz, silica, potash, lime, and magnesia, although the quartz had pre¬ 
viously been, for a long time, treated with aqua regia. Hence it is 
evident that water containing carbonic acid will dissolve out from the 
most barren sands the mineral substances essential to the growth of 
plants. Silica is deposited in different parts of plants, especially in the 
footstalks of the leaves. Hence, in time the cells and vessels of the 
plants become clogged with siliceous particles, and this is one cause why 
the trees of all countries shed their leaves at a certain age. A vernal 
leaf leaves only a minute quantity of ashes ; an autumnal leaf yields a 
very large proportion; from ten to thirty times as much as the wood of 
the same species. The cause of the occurrence of this large quantity of 
mineral matter in the leaves is, that the water of the sap is evaporated 
from them, and, as this goes off, the mineral substances which it held in 
solution are thrown down within the cells. 

[Art. 165.] The principle of combination by definite proportion is 
well illustrated by the atomic theory. By this theory all bodies are 
made up of atoms, which have the same size but various weights. The 
first point, therefore, is to ascertain the weights (or the relative weights) 
of these atoms. This is inferred from the laws of combination of bodies; 
hence this theory can be employed in the illustration but not in the 
demonstration of these laws. An atom of hydrogen is inferred to be 
one-eighth as heavy as one of oxygen, because there is eight times 
as much oxygen as hydrogen in water. The second point is to ascer¬ 
tain the number of atoms in each compound atom. Thus, in the case 
of water, there is supposed to be but one atom of oxygen to one 
of hydrogen. With the relative weights thus determined, and also the 
number of atoms of hydrogen and oxygen in each compound atom of 
water, we apply a third principle of the atomic theory, which is that 
atoms are indivisible. No other combination between oxygen and hy¬ 
drogen can be found except one of whole atoms, and therefore any other 
compound of these elements must consist of 2, 3, 4, &c., atoms of hydro¬ 
gen, united with 2, 3, 4, <fcc., atoms of oxygen. But this method of com¬ 
bination exactly doubles, trebles, <fcc., the quantity of hydrogen or that 
of oxygen in the mass, by doubling, trebling, &c., the number of hydro¬ 
gen or oxygen atoms. This theory, therefore, accounts for the exactness 
of the laws of combination, and upon this fact is grounded the conviction 
of its truth. The atomic theory also illustrates the method of inferring 
the relation between two elements from their relation to a third. Thus, 
having ascertained the atomic weight of oxygen to be 8 from its com¬ 
bining with hydrogen in the ratio of 8 to 1, and that of sulphur to be 
16 from its combining with hydrogen in the ratio of 16 to 1, we con¬ 
clude that sulphur unites with oxygen in the ratio of 16 to 8, if one 
atom of sulphur unites with one of oxygen, for these numbers stand for 
one atom of each of these elements. If two atoms of oxygen unite with 
one of sulphur (sulphurous acid), we double the number 8, the other re¬ 
maining the same, and the ratio of 16 to 16 expresses the relative quan¬ 
tities of sulphur and oxygen in this compound. If three atoms of oxy¬ 
gen unite with one of sulphur (sulphuric acid), we treble 
the-number 8, the number 16 remaining, and 16 to 24 
expresses the relative quantities of sulphur and oxygen 
in this compound. This theory may also be applied to 
illustrate the difference between chemical affinity and 
cohesion. A quantity of sulphuric acid, for example, 
according to this theory, is made up of several groups 
of compound atoms. In fig. 112 these groups are 


Fig. 112. 





EXPERIMENTS. 


335 


represented, the sulphur atoms being marked S, and the hydrogen 
atoms being dotted. That force which holds the atoms of each group 
together is called chemical affinity; that which holds all the com¬ 
pound atoms in one mass is termed cohesion. Water opposes cohesion 
by separating these groups from each other. Heat and various other 
agencies do the same. 

(80.) Coiled wire and watch-spring, zinc filings and red hot charcoal, 
will burn in nitrous oxide. A match made of thin tissue paper, which 
has . been dipped in a solution of nitrate of ammonia, will re-light in the 
gas much more readily than a common lamp-lighter. By the combustion 
of this match, nitrous oxide is evolved in intimate contact with the vege¬ 
table fibre, and therefore the match will often of itself burst into a 
flame, when lighted with a coal of fire; Phosphorus explodes when a 
small piece (size of a pin head) in a platinum spoon is immersed in 
nitrous oxide, and touched with a thick iron wire heated to whiteness. 

(81.) Dip a long slip of wood in melted sulphur, so. that about one 
half may be covered. Light it, and, while feebly burning, introduce it 
into a jar of nitrous oxide gas. The flame will be instantly extinguish-' 
ed. Withdraw the match, inflame it again, and when the flame is vivid 
immerse it a second time. The flame will now be maintained with 
great splendor, of a delicate red color. 

(82.) This mixture maybe exploded in a wide-mouthed phial, covered 
with a towel, or in bubbles blown from a gas bag. The explosion is 
accompanied with a loud report. A bubble of phosphuretted hydrogen 
(179.) passed into ajar of nitrous oxide gas, will explode with a bright 
flame. Sometimes these bubbles do not explode at once. In this 
case, they should not be allowed to accumulate. Tremendous explo¬ 
sions have occurred by inattention in this respect.—The action of this 
gas upon the animal system may be ascribed to its oxidizing effects. 
Oxygen is but slightly absorbed by watery fluids, but this gas is taken 
up by them to a very great extent. When introduced into the lungs, 
it is rapidly dissolved in the blood, and carried by the circulation into 
every part of the body, oxidizing whatever is in its course,—thus pro¬ 
ducing warmth, and acting upon the brain and nervous system. 

(83.) Paste a slip of litmus paper within a glass jar near the bottom, 
and fill the jar with nitric oxide. This will not change the color of the 
litmus paper. Now pass up atmospheric air, and the litmus paper will 
be immediately reddened. The same experiment may be performed in 
a more striking manner, by causing the jar to stand in-a solution of lit¬ 
mus, or in cabbage liquor, previously made green by an alkali. Oxy¬ 
gen gas produces a more striking effect than common air, and if both 
the oxygen and the nitrous oxide are pure, the mixture (hyponitric 
acid) will be entirely absorbed by the cabbage solution, and this will 
rise and fill the jar. 

(84.) A mixture of this gas with sulphuret of carbon burns with a 
blue flame. 

(85.) By passing this gas through lime-water, it may be freed from 
the carbonic acid which it often contains. It will then not affect litmus 
paper or litmus solution. 

(86.) A gas jet for burning this gas may be made by bend- Fig. 113. 
ing a lead tube, as shown in Fig. 113. The holes in this jet 
should be as large as a pin’s head. This gas will not burn as 
readily as the illuminating gases, and therefore requires much 
larger orifices in the jet. Some simple forms of gas jets 
which may be used for this gas, or for the illuminating gases, according 



336 


ELEMENTS OF CHEMISTRY. 


to the size of the orifices , are represented in the accompanying figures. 
These may be made- of tin, tipped with a small piece of lead tube, a, 
by which they may be screwed on to the transfer jar, or to the stopcock 
of the gasometer. A red hot iron may be used to inflame carbonic ox¬ 






ide and hydrogen gases, but it will not kindle the illuminating gases (p. 

121 ). 

(S'?.) That even phosphorus is not inflamed unless oxygen be present, 
may be shown by placing a piece of considerable size in a test tube. 
The phosphorus will at first take fire, but will be almost immediately 
smothered in its own fumes. It may now be heated quite hot, without 
further combustion, and appears like a quiet liquid beneath a stratum 
of white fumes. Into this hot and melted phosphorus, dip a stick which 
is somewhat longer than the test-tube, and suddenly draw it out to the 
air. A portion of phosphorus will adhere to the stick, and will burn 
on coming in contact with the air, with a vivid and almost dazzling 
flash.—When a burning match is held upwards, it soon goes out, be¬ 
cause the flame of the burning does not communicate heat to the part 
not burning ; but when the match is held downwards, the combustion 
is continued, because the flame in this case heats the part not burning 
to the temperature requisite for combustion. 

(88.) This experiment may be exhibited on a small scale by heating 
the nitre, charcoal, and sulphur, in three 'fratch crystals, or in three 
metallic disks of similar form. To show the experiment on a larger 
scale, take a large test-tube, supported by an iron wire around the rim, 
and into this tube put the nitre and heat it quite hot, then pour in some 
dry charcoal powder. Another method is to heat in a crucible 1-2 oz. 
of nitre to a red heat, and then add 1-4 oz. of powdered charcoal. A 
most beautiful combustion will take place, with almost explosive energy. 
This experiment appears to the best advantage when the nitre is melted 
in a Florence flask. When the powdered charcoal is added, a most 

splendid combustion in the form of a vol¬ 
cano takes place. As the flask is usually 
melted by the intensity of the combustion, 
it is necessary to perform the experiment 
over the pneumatic cistern or a basin of 
water. 

Place the glass cylinder of a lamp over 
a lighted candle. The candle will soon be 
extinguished, because no fresh air can en¬ 
ter from beneath. The candle is also ex¬ 
tinguished when the cylinder is covered at 
the top, although the cylinder is so held 
that the air can gain admittance from 
below. In this case the candle is extin¬ 
guished by the burnt gases which surround 
its flame and exclude the oxygen of the 
air. But if the cylinder is placed uncov¬ 
ered, on two pieces of wood, the candle 
continues to burn quietly, and by holding a taper recently extinguished 


Fig. 114. 



















EXPERIMENTS. 


337 


near the lower opening, it will be obvious, from the direction of the 
smoke, that air rushes in at the bottom but escapes at the top, and thus 
a constant supply of oxygen is afforded to the flame. If the upper part 
of a cylinder of a lamp be divided into two channels by a partition down 
the middle (Fig. 115), the candle will then burn, even if access of air be 
cut off from below. The smoke of a glimmering taper will be drawn 
inwards on one side, and expelled from the other, as indicated by the 

arrows in the figure. In 

Fig. 115. common lamps, air has ac- Fig. 116. 

cess only to the outside of 
the flame; hence eombus- 
tion goes on only at the 
circumference, and the in¬ 
terior of the flame is there¬ 
fore dark. But if air be 
admitted into this interior 
portion, the dark part dis¬ 
appears. The carbon of 
the flame is in this way ig¬ 
nited on both surfaces of 
the flame, and more in¬ 
tensely by reason of the 
greater heat. On this prin¬ 
ciple, the Argand lamps 
(Fig. 116) are constructed. 

The air is admitted within 
at a, a , and without at b, b, 
as shown by the arrows, and may be made evident by the smoke of a 
taper. 

(89.) For an inextinguishable match, mix together nitre 4, gunpowder 
2, sulphur 1, all in a dry state. Prepare some paper cylinders of thick 
and hard paper, and place them over nails driven in a board, to support 
them in an upright position. Now fill them with the mixture, ramming 
it well. A single nail will in this way hold the paper cylinder firmly 
to the board. When set on fire these cylinders cannot be extinguished, 
and will even burn under water. 

(90.) Upon a board about 2 feet long place several heaps of gunpow¬ 
der about 2 inches apart, wet the powder with turpentine, and connect 
the heaps with each other by moistening the space between with turpen¬ 
tine. Now apply flame to the moistened heap of powder at one end 
of the board. The flame will travel over this heap and along the line 
of gunpowder, without exploding it, to the end, but after the turpentine 
is nearly consumed, the powder heaps will explode, beginning with the 
one at the end where the flame commenced, and ending with the most 
distant pile. The little turpentine that remains in the gunpowder will 
add greatly to the intensity of its combustion. Alcohol or ether may 
be used instead of, or in connection with turpentine. Place a piece of 
phosphorus on some cotton wet with alcohol. Inflame the alcohol, and 
it will burn without kindling the phosphorus until it has nearly burnt 
out. Ether or turpentine may be substituted for the alcohol, and sul¬ 
phur dr gunpowder for the phosphorus. Alcohol may be inflamed on a 
white linen handkerchief without injury to the handkerchief, or on the 
hand without inconvenience, although at the point of the flame glass may 
be melted. Float a hoop on the water of the pneumatic cistern, and fasten 
it to the sides of the cistern, so that it will maintain its position on the 

15 





















3B8 


ELEMENTS OF CHEMISTRY. 


water. Fill the space within the hoop with alcohol or turpentine, which 
will float on the water, and set the alcohol on fire. Within the tall col¬ 
umn of flame thus produced, the hand may be inserted, by carefully 
bending the arm through the water below and the alcohol Wi thin the 
hoop. 

(91.) The hollow nature of flame may be shown by thrusting one end 
of a tube slightly inclined within the wick of a burning lamp. A por¬ 
tion of white gas will issue from the other end of the tube, sometimes in 
sufficient quantity to be inflamed. 

(92.) The following method of illustrating the subject (on the black 
board) may be employed: Flame may be considered 
as made up of three parts, of which the inner consists 
of both carbon (0) and hydrogen (H). The second 
portion consists of carbon (C), the hydrogen being 
burnt, the heat from which ignites the carbon to a high 
degree of intensity. The third part is the burning 
carbon, and hence is marked C0 2 , or carbonic acid, 
which is there in the process of formation. In this 
part the carbon not being so intensely ignited, gives 
out less light. Watery vapor (HO) also exists in this 
part, derived from the combustion of the hydrogen in 
the first part of the flame.—All combustible substances 
which contain carbon and hydrogen burn in a similar 
manner. Hence, when a billet of wood (especially 
green wood) is thrown on a hard coal fire in a close 
stove, a great volume is given off for a very long time, 
without any apparent combustion of the hard coal, or even of the carbon 
of the wood. This is therefore a very economical way of building fires. 
In whatever situation any kind of wood is burnt, the carbon remains be¬ 
hind, and continues to glow after the hydrogen has been consumed, and 
the flame has consequently ceased.—Insert some meshes of fine platinum 
wire in the flame of an alcohol lamp. The flame, before but feebly 
luminous, now gives out a very bright light, owing to the ignition of 
solid matter which is not burnt.—The very bright light which phos¬ 
phorus produces in burning is owing to the ignition of the snowy parti¬ 
cles of phosphoric acid thus produced.—The carbon of gas may be con¬ 
sumed (instead of being ignited) in the following manner, and the result 
will be a loss of illuminating power : Take a wide tube, or a lamp 
chimney, and pass through it a current of gas, so that air from beneath 
is mixed freely with the current in the tube. As the current issues from 
the top of the tube, place over it a wire gauze, which will have the 
effect to mix the air and gas more perfectly. If this mixture is now 
lighted, it will burn with no loss of heat, but with feeble illuminating - 
power . The length of the tube being important only to mix the gas and 
the air, it may be much diminished by placing a wire-gauze about the 
middle of the tube, in addition to the one at the top.—Anything which 
tends to consume more effectually the carbon of common flame so far 
diminishes its illuminating power. For this reason a tall glass chimney 
is generally very wasteful, as it increases both the heat and the draft 
of air, and thus diminishes the illuminating power, except in case of 
those fluids where the opposite evil is to be avoided—the escape of un¬ 
burnt carbon or smoke into the room. 

(93.) The particles of carbon in the previous experiment (92.) being 
completely consumed, it will be found that no soot will be deposited, 
this being the unconsumed carbon of the flame. 


Fig. 117 




EXPERIMENTS. 


339 


(94.) A copper wire twisted into a spiral form (Fig. 118) will so cool 
the flame of a lamp into which it is placed as to 
extinguish it, but if the spiral be previously heat- Fig. 118. 

ed to redness, the flame will not be extinguished. ' ' "'' a * 

It should be about an inch in diameter, so as to 
pass over the flame. A jet for the oxy-hydrogen 
blowpipe (176.) has been constructed on this principle. A tube of brass 
about 4 inches in diameter is filled with pieces of fine brass wire, which 
are all tightly wedged together by a pointed rod driven into the centre 
of the bundle. This arrangement presents a great number of metal 
tubes, very long in proportion to their diameter. The cooling power of 
this great surface of metal is such as to prevent the possibility of the 
passage of flame, even that of oxygen and hydrogen. 

(95.) To illustrate the action of the blowpipe flame, make a bead (see 
“ chemical processes ”) with borax and the oxide of chrome, or the oxides 
of cobalt, manganese, iron, <fcc.; also with earbonate of soda and man¬ 
ganese. Show the intense light produced by the flame on lime. 

(96.) Bubbles of this gas may be burnt as they rise from the surface 
of water. The orifices of gas jets (Expt. 86.) for burning this gas should 
be exceedingly small, not larger than the wire of the smallest pins. 

(97.) The mixed gases may be exploded in soap bubbles, or as they 
rise from the surface of water. 

(98.) The old temples of the Guebres, or fire worshippers, at Baku, 
on the western shore of the Caspian sea, are built over jets of inflamma¬ 
ble gas, which issue from apertures in the earth. Within an area of 
two miles in circumference if holes be made in the earth gas immediate¬ 
ly rises, and may be set on fire by a lighted torch. Jets of inflammable 
gas have been observed on a mountain in the island of Samos; also in 
Bengal in a temple at Chittagong, and in many other places. A current 
of inflammable gas was discovered in 1828, in the bed of a rivulet on 
the road between Edinburgh and Glasgow, about 7 miles from Glasgow. 
It was said to be emitted for more than half a mile along the banks of 
the rivulet. In one place where a large number of jets issued near each 
other, they were set on fire and burnt uninterruptedly during five 
weeks, giving the clay soil the appearance of powdered brick. 

(98.) Albany, N. Y., coal, Virginia and New Castle, 40 cts. 100 ft. gas. 


Baltimore, Md., do. 
Boston, Mass., do. 

Buffalo, N. Y., do. 
Charleston, S. C., do. 
Cincinnati, 0., do. 

Hartford, Ct., do. 

Rochester, N. Y., do. 
Lancaster, Pa., resin, 
Norfolk, Va., do. 


do. and some resin, 40 do. 

Pictou and some Cannel, 85 do. 

Ohio and Pennsylvania, 35 do. 

Cannel, 60 do. 

Pittsburg and Youghany, 30 do; 

Newcastle, 40 do. 

American Cannel, 40 do. 

30 do. 

__ _ _ 70 do. 

(99.) In front of the retorts in the figure are seen two long bars, one 
of which light colored is the catch, the other dark shaded is attached to 
the lid of the retort. Through the light colored bar or the catch a screw 
passes, by turning which the lid is pressed closely to the retort. When 
the retorts are to be opened the screws are unbound, the light colored 
bar is lifted up from the catch, and swung with the screw attached to it 
wide open, the lid is then lifted off by the dark colored bar or the han¬ 
dle which is attached to it. Before the lid is again applied to the re¬ 
tort. a mixture of clay and sand is applied around the edge, which makes 
the junction with the retort air tight when the lid is screwed up. 




340 


ELEMENTS OF CHEMISTRY. 


[Art. ITS.] It lias been recently proposed to use a solution of sulphate 
of manganese or sulphate of iron (copperas) as a substitute for the lime 
purifiers in gas works. In the washing vessels, the gas comes in con¬ 
tact with the manganese solution in the form of a kind of water-fall, 
under a pressure of 4 to 6 inches. Sulphate and muriate of ammonia, 
which dissolve, and carbonate and sulphuret of manganese, which are 
precipitated, are the resulting compounds. 

The bituminous slate of Autun, in France, is now used for the manu¬ 
facture of gas. It is first distilled, and the oily products employed in 
the following manner : Three cylinders are walled in an upright posi¬ 
tion in a furnace, and are kept red hot. The first two are filled with 
wood charcoal, which is replaced from time to time as it is consumed; 
the last is filled with a chain and pieces of iron. A thin stream of water 
flows into the first cylinder, and is there converted, in contact with the 
red hot coals, into carbonic oxide and hydrogen, a process which is com¬ 
pleted in the second retort, from whence both gases enter the third re¬ 
tort, in which a stream of the slate oil is being decomposed by the red 
hot iron. The decomposed vapors of the water (carbonic oxide and hy¬ 
drogen) form here, with the vapors of the slate oil, the illuminating gas. 
This is said to be produced of better quality, and also in much larger 
quantity, than by the old method. The improvement in quality is due, 
to a great extent, to the preservative action of hydrogen on olefiant gas, 
preventing its carbon from being deposited in those graphite-like incrust¬ 
ations common in gas retorts. 

A patent has also been taken out in England for a method of manu¬ 
facture based.on the same principle as the decomposition of water. 

(100.) Ammonia for the purposes of experiment, is more conveniently 
prepared by distilling liquid ammonia in a Florence flask or a retort. 
The gas will issue with great rapidity, and may be collected in a per¬ 
fectly dry flask or tube. When the flask is full, a feather dipped in hy¬ 
drochloric acid and held near the mouth, will give dense white fumes. 
The flask may now be corked, but the gas cannot be long retained in 
this way, as it will escape through the pores of the cork. 

(101.) Fill ajar with ammoniacal gas and place in it a piece of fresh 
charcoal; after 24 hours the whole of the ammonia will be absorbed, 
no odor remaining. 

(102.) Fill a long glass tube with ammoniacal gas, and when quite 
full, plunge the lower end in a vessel of water ; the absorption of the gaa 
will be so rapid and so complete, that the water will rush with force to 
the top of the tube, and completely fill it.—Fill a bottle with ammonia¬ 
cal gas, and drop into it a piece of ice; the ice will almost instantly be 
dissolved, and great cold will be produced by the absorption of latent 
heat in its liquefaction. If this experiment be performed over mer¬ 
cury, the mercury will rise and fill the jar or bottle. 

(103.) Pass a stream of the gas through a solution of litmus previous¬ 
ly reddened by a little acid, the color will be changed to a deep blue.— 
A very dense and beautiful blue color is produced by passing a stream 
of ammoniacal gas through a solution of sulphate of copper (blue vitriol), 
so dilute as to be colorless. This consists of the hydrated oxide of cop¬ 
per, which is insoluble in water (and, therefore, is at first precipitated), 
but is dissolved in the water of ammonia, formed by continuing the 
stream of gas. 

(104.) Ammonia may be thus detected in a quill, or in other animal 
matter, when burnt. -—A stream of chlorine passed into a very strong 
solution of ammonia in a phial decomposes the ammonia, and each bub- 


EXPERIMENTS. 


341 


ble in so doing bursts into a flame, with a slight explosion.—If the ex¬ 
periment be reversed, and gaseous ammonia be passed into strong chlo¬ 
rine water, the ammonia will inflame, and continue to burn with a pale 
lilac flame, producing chloride of ammonium (216.) and giving off nitro¬ 
gen.— Fill two bottles, one with gaseous ammonia and the other with 
chlorine. Place them neck to neck, the one containing ammonia being 
uppermost. The gases will mingle with each other notwithstanding the 
difference of their specific gravities (186.), and their union will generally 
be attended with flame at the mouth of the bottles.—Pour a solution of 
ammonia into chlorine water. In this case also chloride of ammonium 
will be formed and nitrogen given off. 

(105.) The ammonia from guano and other rich organic manures may 
be detected in this way. 

(106.) Cut a piece of potassium with a knife; its bright metallic sur¬ 
face will soon tarnish, and become covered with a white crust of potash 
or oxide of potassium. Place a small piece of potassium on a red hot 
iron after removing the naphtha adhering to it by blotting paper. It 
will immediately take fire. By its combustion it will form an orange- 
red powder, which is the peroxide of potassium. If burnt in oxygen 
it produces the same powder.. If to this powder a few drops of water 
be added, a part of the oxygen is disengaged with effervescence, and 
potash remains in solution.—Potassium takes fire instantly when placed 
in chlorine, forming a chloride of potassium.—When thrown on water a 
part of it combines with the oxygen of the water, forming potash, while 
the other part unites with the hydrogen to form potassuretted hydro¬ 
gen. This gas being very inflammable takes fire, and by its combustion 
is converted into potash and water. Towards the latter part of this 
experiment the potassium explodes, and throws about the potash with 
which it is covered with considerable force.—The same action wfil take 
place if potassium be thrown on ice.—The decomposition of water by 
potassium may be shown by wrapping a piece of this metal in paper, 
and introducing it underneath a test-tube full of water, inverted over a 
basin on the pneumatic cistern. The potassium will rise in the test- 
tube to the top, and the moment the water reaches it through the pa¬ 
per, part of it will be decomposed, the oxygen combining with the 
potassium, while an equivalent portion of hydrogen is formed in the 
tube. The hydrogen may be inflamed by applying a lighted match.— 
Potassium dropped into sulphuric acid at the bottom of a long tube, will 
decompose the acid with the evolution of heat and light.—To 2 grs. of 
iodine in a test-tube 4 or 5 inches long add a grain of potassium, and 
hold the tube for a second or two in the flame of a spirit lamp. An in¬ 
tense light and energetic^rction are produced, and the potassium and 
iodine unite, forming iodrcre of potassium. As the tube is generally 
broken by the violence of the action, the hand should be defended by a 
glove, and the mouth of the tube turned away from the operator.—Sul¬ 
phur also combines with potassium with the evolution of heat and light, 
forming sulphuret of potassium.—Half a grain of sulphur may be used 
with a grain of potassium.—Take a small globule of potassium and a 
small piece of phosphorus of the size of a split pea. Press the two sub¬ 
stances together with the point of a knife on a marble slab, or a warm 
iron, and they will unite with a vivid combustion, forming phosphate of 
potash.—Tin and potassium unite when melted together in equal' parts 
in a crucible. Light is evolved at the instant of their union.—In like 
manner potassium and^ metallic arsenic unite, forming arseniuret of 
potassium. 


342 


ELEMENTS OF CHEMISTRY. 


(10?.) Place a globule of mercury about the size of a pea, and a glob¬ 
ule of potassium about half as large, on a sheet of writing paper. By 
lifting the paper bring the two metals into contact. The instant this 
takes place, they will combine with the evolution of heat. The amalgam 
at first fluid, on account of the heat, will soon become solid, although a 
small quantity of a solid has been combined with twice the amount of a 
liquid metal. Put the amalgam into a tea-cup containing warm water. 
The potassium will here show its greater affinity for oxygen (of the 
water) than for mercury, by quickly combining with the water, while 
the mercury is reduced and falls to the bottom. Hydrogen is set free 
by the decomposition of the water. If the amalgam is wrapped in a 
piece of muslin and suspended in a tall jar just beneath the surface of 
the water, the mercury will ooze through the muslin and fall to the bot¬ 
tom, as the amalgam undergoes decomposition. A similar effect will 
take place when this amalgam is exposed to the air, but less rapidly. 

(108.) A piece of dry potash exposed to the air in a very few minutes 
will become quite damp, and soon melt away. 

(109.) The following mixture forms a deflagrating powder; nitre 4, 
sulphuret of antimony 2, sulphur 1. These constituents are well mixed 
on a sheet of paper with a wooden or ivory spatula. A dram, or 
larger quantity, is placed on a piece of dry wood or iron, and fired with 
a red hot iron. Instant deflagration accompanied by a great heat and 
dazzling light takes place.—The following mixture is a fulminating pow¬ 
der ; nitre 10 grs., phosphorus 2 grs. This mixture explodes violently 
when struck on an anvil with a hot hammer.—Mix gunpowder with 1-3 
its weight of powdered glass. Place a little of this mixture on an anvil, 
and strike it a heavy blow with a hammer. It will generally explode 
with a loud report.—Into a crucible containing red hot nitre, throw a 
few filings of arsenic, antimony, bismuth, zinc, iron, lead, tin, copper, &c. 
The combustion will be different in the different metals, and sometimes 
be attended with detonation. The same effect takes place with the me¬ 
tallic sulphurets as with the metals.—Canada balsam greatly augments 
the explosive energy of gunpowder. The flash of the mixture is as in¬ 
stantaneous as that of gunpowder, and the volume of flame is much 
greater. A small quantity of gunpowder may be flashed in a wide¬ 
mouthed phial without exploding it, but if the same amount be mixed 
with a little thick Canada balsam and put into the phial, and fired by a 
slow match, the phial will be blown to pieces with a very loud report. 

(110.) Pulverize 6 drams of nitre and 5 drams of sal ammoniac, and 
add 2 oz. of water to them. This mixture will sink the thermometer 
from-f-50°to-f-10 0 or 40°, and will freeze oil of turpentine, wine-wa¬ 
ter, sea-water, milk, and vinegar. 

(111.) The experiments given under potsHum may be repeated with 
sodium. 

(112.) Soluble glass (soluble on account of the great proportion of 
alkali which it contains): pearlash 10, sand 15, charcoal 4. One part 
of this glass is dissolved in about 4 of water.— Plate glass : white sand 
120, carbonate of lime 2, soda 45 to 48, fragments of glass of like quali¬ 
ty 100, oxide of manganese 1-4.— Flint glass: fine white sand 120, 
well purified pearlash 40, litharge or red lead 35, nitre 13, and a small 
quantity of the black oxide of manganese.— Crown glass: fine white 
sand 100, carbonate of lime 12, carbonate of soda calcined 45 to 48, 
clippings of crown glass 100, and a small quantity of manganese.— 
Bottle glass: common white or yellow sand 100, coarse kelp (carbonate 
of soda prepared from sea-weed) 30 to 40, lixiviated ashes 160 to 1?0, 


EXPERIMENTS. 


343 


fresh'wood ashes 30 to 40, yellow clay or brick earth 80 to 100, broken 
glass 100. 

[Art. 206.] Dissolve 3 parts of Glauber’s salts in 2 of boiling water, 
and pour the solution while hot into a phial, and cork the phial tightly. 
No crystallization will take place, even when the solution is perfectly 
cold, but if the cork be removed, the crystallization will proceed with 
rapidity. If this does not take place immediately, the introduction of 
any solid matter commences it, and the temperature at once rises. 

223. Freezing mixture with sal ammoniac. Sal ammoniac 6 drams, 
saltpetre 5 drams, water 2 ounces. This mixture will sink the ther¬ 
mometer from 50° above to 10° below zero. It freezes oil of turpen¬ 
tine, wine, water, sea-water, milk, and vinegar.—Dust the hand with pow¬ 
dered sal ammoniac, or place a tea-spoonful of the powdered salt in the 
band, and add a table-spoonful of water. The sensation of cold will be 
very strong. 

Page 181. Colors of porcelain. Dark purple by manganese, rose 
color by gold precipitated by tin, orange by antimony, blue in different 
shades by antimony, green by copper, also by nickel with potash, fine . 
brown by nickel and umber.— Action of alum on the vegetable colors. 
Pill three wine glasses with cabbage liquor, and add to one a little 
muriatic acid, to the second a solution of alum, and to the third a solu¬ 
tion of potash. The liquor in the first glass will assume a beautiful 
crimson, that of the second a purple, and the third a bright green. An 
infusion of larkspur and many other flowers will be changed to a green, 
by a solution of alum. 

Colored glass is produced by the addition in small quantities of various 
metallic oxides. Yellow is obtained either from oxide of antimony or oxide 
of silver, lied by gold or by suboxide of copper. 

£Art. 254.] Fliut glass may be beautifully colored with manganese by 
pounding it up in a mortar and melting some of the powder thus ob¬ 
tained with a minute quantity of the black oxide of manganese, either 
before the blowpipe, or in a crucible on the fire.—Mix a minute quantity 
of manganese with 5 times its weight of borax, and with a brush lay 
this mixture over an unbaked tile or tobacco pipe. Place the tile in the 
furnace until it is baked, and the same amethyst color will be produced. 

268. Sugar of lead 1-2 oz. dissolve in water. Add ten drops of nitric 
acid or a little vinegar. In this solution suspend by a string a piece of 
zinc about the size of a hazel nut, and twist once or twice around the 
zinc a piece of fine brass or copper wire. The end of this wire should 
hang down in a tasteful form, as the lead will be precipitated upon it. 
No part of the wire or the zinc should touch the sides of the bottle. The 
nitric acid or vinegar is added to the solution to dissolve a white cloudy 
precipitate, which is often formed when sugar of lead i3 dissolved in 
common water, or when it is impure. Filtering the solution will an¬ 
swer the same purpose.—A tin tree may be formed by dissolving muri¬ 
ate of tin 3 drs. in water, and adding 10 drops of nitric acid, From this 
solution the tin may be precipitated as the lead in the last experiment. 

272. Blue enamels for porcelain are composed of white enamel and a 
minute quantity of cobalt. White enamel is a composition of pure sand 
3, chalk 1, calcined borax 3; or broken fliut glass 3, calcined borax 1, 
antimoniate of potash 1. The arseniate of cobalt is the most convenient 
form in which this substance can be used, as the arsenic acid is partly 
driven off by the heat, and what remains acts as a flux without produc¬ 
ing any color of itself. The addition of a small portion of nitre often 
brings out a finer color.—The sapphire is imitated by a composition of 


344 


ELEMENTS OF CHEMISTRY. 


white paste 2 oz., and oxide of cobalt 2 dr. 26 grs. White pasters 
composed of white sand first washed and purified with hydrochloric acid, 
and then with water till the whole of the acid is removed. Of white 
sand thus prepared 100 parts are taken to form white paste, with red 
lead 150, calcined potash 30 to 35, calcified borax 10, oxide of arsenic 1. 
These materials are kept in a state of fusion for three or four days. 
The paste thus formed is that from which all the artificial gems are 
formed by coloring with various metallic oxides. 

273. A landscape may be drawn with India ink, and the foliage paint¬ 
ed with muriate of cobalt. Some flowers may be added with acetate of 
cobalt, others with muriate of copper. After the picture is dry, when 
cold only an outline of the landscape will be visible, but when slowly 
warmed the foliage will gradually be brought out of a green color, the 
flowers painted with acetate of cobalt blue, and those painted with 
muriate of copper yellow. These colors will again disappear as the 
picture grows cold. If, however, once strongly heated, they become per¬ 
manent .—Letters may be drawn of these different colors, which will be 
invisible when cold but be brought out by heat. 

Page 197. Fusible alloys of bismuth: bismuth 8, lead 4, tin 1 ; bis¬ 
muth 14, mercury 16, lead 32 ; bismuth 4, lead 4, tin 1, mercury 1 ; bis¬ 
muth 1, lead 2 ; bismuth 3, lead 6, antimony 3.—Melt 2 drams of nitrate 
of bismuth, and pour the melted metal into a dram of mercury. Melt 
also 2 drams of lead and pour it into a dram of mercury. When cold 
these alloys are solid, but when rubbed together they enter into a state 
of fusion with each other.—Letters drawn with the nitrate of bismuth 
when dry are invisible, but are brought out of a white color by immers¬ 
ing the paper in water, and of a black color by exposing them to a 
stream of sulphuretted hydrogen, or touching them with a feather dipped 
in a solution of sulphuret of potassium.—A fine lemon color, the chromate 
of bismuth, is formed by adding chromate of potash to nitrate of bis¬ 
muth. 

282. Miners detect copper in an ore by dropping a little nitric acid 
upon the ore, and after a time dipping a feather into the acid, and wip¬ 
ing it over a polished knife blade. If there be the smallest quantity of 
copper in the ore this metal will be precipitated on the knife. 

Page 203. Yellow letters of the chromate of lead may be formed by 
writing with a dilute solution of chromate of potash on a sheet of paper 
prepared with a salt of lead, as the acetate. 

Page 208. Sometimes a mixed precipitate of the chloride and the sul¬ 
phate of silver is obtained. These may be separated by raising the tem¬ 
perature of the solution to the boiling point, by which the sulphate of 
silver will be re-dissolved, but the chloride will remain undissolved. 
The experiment may be tried by dropping into a glass of water a drop 
of sulphuric acid, and one or two drops of hydrochloric acid. Add a lit¬ 
tle nitrate of silver and the mixed precipitate of the chloride and the 
sulphate will be formed. 

295. Silver is also reduced from its solution by hydrogen, and by 
chloride of ammonium. Silk may be silvered with letters, or flowers, 
or any other figures, by drawing the figure on the silk with the silver 
solution, and exposing it to a stream of hydrogen gas. 

296. The Daguerreotype plate is brought to a high polish by rubbing 
it with tripoli and rotten stone, to which a little nitric acid exceedingly 
dilute has been added to ensure a more effectual cleaning of the plate. 
This plate is next exposed in a box to the vapor which rises from iodine 
at common temperatures, or without the application of heat. In this 


EXPERIMENTS. 


345 


box it is allowed to remain until it has acquired a yellow golden tint. 
It is then placed in a second box containing bromine, the fumes of 
which rising attack the plate and add to the golden color a violet tint. 
The plate is now ready to receive the picture. For this purpose it ia 
put into the camera obscura. After remaining in the camera the proper 
length of time it is removed. The effect has been produced on the plate, 
but this effect is as yet invisible. To “ bring out the picture ” the plate 
is placed in a box containing mercury, and exposed to the fumes of this 
substance for a time. These fumes are raised by the application of a 
gentle heat from a spirit lamp beneath the mercury. In a short time 
the image comes out, and to prevent any further action of light upon 
the picture, the latter is carefully washed in a solution of hyposulphite 
of soda. This substance dissolves off all the sensitive coating of the 
plate, that is all the coating which has not been already acted upon by 
light, and fixed by the processes to which the plate has been exposed. 
The plate is gilded by dipping it into a mixture of the hyposulphite of 
soda and the chloride of gold. This acts like a varnish, fastening the 
picture and giving it a more agreeable yellow tint. 

In “Talbotyping” the pictures are made on paper. Writing paper 
of good quality is washed on one side with a moderately dilute solution 
of nitrate of silver, and left to dry spontaneously in a dark room. When 
dry it is dipped into a solution of iodide of potassium and again dried. 
To hasten this part of the process the papers are now generally dried 
between pieces of blotting or unsized paper. These operations are per¬ 
formed in a room with but little daylight or by candle light. When re¬ 
quired for use these papers are dipped into (or rather floated on, so as 
to prepare only one sensitive surface—so of the processes mentioned 
above) a solution of nitrate of silver, to which acetic acid and gallic acid 
have been added (just before using), and once more carefully dried. The 
paper thus prepared is now introduced into the camera and receives 
the picture. It is so sensitive that exposure to diffuse daylight for one 
second suffices to make an impression upon it, and even the light of the 
moon produces the same effect, although a longer time is required. The 
images when first taken out of the camera are invisible, but are brought 
out by once more washing the paper in the mixture of nitrate of silver, 
acetic and gallic acids, and by warming it before the fire. The picture 
is then fixed by immersion in a solution of bromide of potassium and by 
washing in water. This is a negative picture; that is, all the lights and 
shades are reversed. In order to obtain & positive picture the negative 
is placed over paper prepared for the purpose with chloride of silver, 
and both papers are covered and held together by a glass plate in a 
frame. The frame is then inclined in the full light of the sun, where it 
remains for a short time, till the rays passing through the light parts of 
the negative picture have darkened the paper beneabh, and thus pro¬ 
duced on that paper a reverse picture, or a positive picture. From one 
negative picture, therefore, many positive pictures may be obtained, 
and this is, therefore, one of the advantages of this process over the 

DsiffUGrrGotypc. __... • 

Photographic pictures are now taken upon glass, covered with a thin 
film of albumen, and rendered sensitive to light by a mixture of acetic 
acid and nitrate of silver. Engravings, as recently discovered may be 
copied by exposing them to the vapor of iodine, and then taking im¬ 
pressions upon paper previously coated with paste or starch and mois - 

ened with dilute sulphuric acid. ... „ 

There are many other methods of forming pictures on paper, whic 

15 * 


346 


elements of chemistry. 


have received the names.of “ chromatype,” or colored pictures, “ ener- 
giatype,” from the extreme sensitiveness to light of the paper prepared 
by this method, “iodatype,” where the picture is formed with starch and 
iodine, &c. All these processes, however, proceed on the same general 
plan. 

One great advantage of Talbotypes over Daguerreotypes is that the 
former can be seen in all positions, while the latter being formed on a 
reflecting surface can be seen only in one position. Talbotypes are now 
made in great perfection in some parts of the country, and perhaps are 
destined to supersede, in a great degree, Daguerreotypes. 

Page 214. Melt a globule of tin to a white heat, and drop it upon an 
inclined board, it will break into a multitude of small globules, which 
burn with a bright light as they roll down the board, and mark their 
course by lines of white oxide of tin.—Tin may be reduced to a finely 
divided state by pouring it while melted into a wooden box the inside 
of which has been rubbed with chalk, and by shaking it in the box till 
it is cold.—In covering plates of iron with tin, the iron is thoroughly 
cleaned by rubbing with sand. It is then steeped in water acidulated 
with sulphuric acid. When taken out and dried the plates are gently 
heated in an oven, being first rubbed over with grease to prevent oxida¬ 
tion. In this state they are immersed in melted tin, which not only ad¬ 
heres to the surface, but in a great measure penetrates the whole plate. 
—Tin plate may be beautifully crystallized by heating it on or before a 
clear fire until so hot that a drop of water let fall upon it will boil. A 
wash is then applied to the surface consisting of equal parts of nitric and 
hydrochloric acids, after which the plate is rinsed in water to remove 
the acid adhering to its surface. This will be beautifully crystallized. 
The appearance of the plate may be greatly varied by making one part 
hotter than the rest before applying the wash. 

Page 216. Antimony may be fused like tin under the blowpipe, and 
thrown on an inolined board. The small globules into which it divides, 
burn with a very lively flame, throwing out on all sides brilliant sparks. 
—Metal supports for iron pins are fastened into porcelain door knobs 
with a solder of lead 35, antimony 1. This solder melts at a very low 
temperature. It is poured into the knob in such a manner as to catch 
in three small holes, the excess being removed by a small tool contrived 
for the purpose. 

Detonating powder, with sulphuret of antimony, may be prepared with 
the following proportions: sulphuret of antimony 6 grs., chlorate of 
potash 3 grs. Place a little of the mixture on an anvil, and strike it a 
sudden blow*with a hammer. It explodes with a loud report and a 
vivid flame.— Deflagrating powder: sulphuret of antimony 2 oz., nitre 
4 oz., sulphur 1 oz. Mix the materials well on a sheet of paper with a 
wooden or ivory spatula, and lay about a dram or more of the composi¬ 
tion on a piece of wood or iron. Fire with a red hot iron. Instant de¬ 
flagration with dazzling light and great heat will be produced. 

Page 219. Distinguishing reactions of arsenical and antimonial spots 
produced by Marshs test. If a drop of bromine is placed on-a saucer, 
and a capsule containing arsenical spots inverted over it, the spots take 
a very bright lemon-yellow tinge in a short time. Antimonial spots, 
under the same circumstances, are acted on much more rapidly (in 
about 5 seconds, at a temperature of 52° Fah.), and assume an orange 
shade. . Both become colorless if exposed to the air, and are again re¬ 
stored if treated with a strong solution of sulphuretted hydrogen. The 
eecondary yellow of the arsenical spots disappears on the addition of 


EXPERIMENTS. 


347 


ammonia, while that of antimonial spots remains untouched. A con¬ 
centrated solution of iodate of potassa turns arsenical spots of a cinna¬ 
mon-red, and dissolves them almost immediately. On antimonial spots 
it has no visible effect within three or four hours. 

[Art. 303.] Mix a few grains of metallic arsenic with twice its weight 
of gunpowder and an equal weight of nitre. Grind the mixture well, 
and set fire to it. The arsenic will burn with great splendor, producing 
a whitish blue flame. 

306. White fire, nitre 24, sulphur 7, realgar 2, pulverized and mixed 
intimately. 

308. If gold leaf be dropped into two glasses, one containing pure nitric 
acid, and the other hydrochloric acid, the gold will remain undissolved 
in both. But if the contents of the two glasses be poured together, the 
metal will be entirely dissolved and disappear.—Moisten white satin 
ribbon or silk with a diluted solution of gold, and while moist, expose it 
to a stream of hydrogen or sulphurous acid gas. These gases will de¬ 
compose the oxide of gold, and deposit the gold in a uniform coating 
on the silk. In this way any ornamental figures may be laid upon silk, 
the gilding of which will be permanent. 

310. An ethereal solution of gold for gilding is prepared by agitating 
with a solution of nitro-muriate of gold about a fourth part of ether. 
When thoroughly mixed, allow the solution to stand until the ether 
separates in an upper stratum. This will contain the ethereal gold, and 
may be carefully poured off into another vessel. A polished steel in¬ 
strument dipped into this solution, and immediately after into water, 
becomes coated with reduced gold. An ethereal solution of platinum 
may be prepared in the same way. 

339. For 12 gallons of ink take nutgalls 12 lbs., sulphate of iron 5 
lbs., gum Senegal 5 lbs., water 12 gallons. The nutgalls are bruised and 
boiled for three hours in a copper vessel of a depth equal to its diame¬ 
ter. Nine gallons of water are at first used, and the remainder added 
to replace what is lost by evaporation. The decoction is emptied into a 
tub, allowed to settle, and the clear liquor drawn off. The lees are then 
drained. To this decoction of nutgalls the gum dissolved in a little hot 
water and filtered is added. The sulphate of iron is also separately dis¬ 
solved, and well mixed with the other ingredients. The color darkens 
by degrees in the air as the iron becomes peroxidized. When ink is 
used in a pale state the writing is more durable, because its particles are 
then finer and penetrate the paper more intimately. Mould in ink is 
owing to the growth of a minute fungus. It may be prevented by the 
addition of a few bruised cloves or other aromatic perfumes. Write 
with a weak solution of sulphate of iron. When dry the writing will be 
invisible. By wetting a feather with tincture of galls and drawing over 
the letters they will be brought out of a black color. 

379. For red sealing wax melt together with a very gentle heat shellac 
48, Peruvian balsam 1, and add gradually the finest cinnabar which has 
been thoroughly levigated. Mix the ingredients well together by stir¬ 
ring Or use the following ingredients: pale shellac 1-4 oz., turpentine 
1 dram, cinnabar 1 dram, prepared chalk 3-4 dram.—For black sealing 
wax mix shellac 2 with ivory black 1, and perfume with a little Peru¬ 
vian balsam or storax. The great seals applied to certain legal docu¬ 
ments in England are made of a mixture of Venice turpentine 15, olive 
oil 5, wax 8, melted together and colored with red lead. Chrome ye - 
low, azure blue, mountain green, lamp-black, and bronze powder, are 
some of the substances used to color sealing wax. 


348 


ELEMENTS OF CHEMISTRY. 


384. When potassium is heated in cyanogen it takes fire and burns in 
a very beautiful manner. 

387. Write with a weak solution of sulphate of iron. When dry the 
letters will be invisible, but a feather dipped in ferrocyanide of potass¬ 
ium will bring them out of a beautiful blue color.—Reddish-brown let¬ 
ters may be formed by using sulphate of copper instead of sulphate of 
iron. 

401. Colors for Chemists’ windows. — Green, verdigris dissolved in 
water, and acetic acid added;—sulphate of copper 2 oz., salt 4 oz., wa¬ 
ter 20 oz.; add solution of sulphate of copper to a solution of bichromate 
of potash ;—add nitric acid to a solution of sulphate of copper. Blue, 
liquid ammonia added to a weak solution of sulphate of copper;—Prus¬ 
sian blue 10 grs., oxalic acid 20 grs., water 16 oz. Lilac , dissolve zaffre 
(impure oxide of cobalt) in hydrochloric acid, filter, and add carbonate 
of ammonia in excess; to this add ammonio-sulphate of copper'until the 
proper color is produced. Yellow , quercitron bark, or Indian yellow, 
or saffron, (the last to be preferred), boiled in water. Orange, dissolve 
bichromate of potash until the required tint is produced ; sometimes sul¬ 
phuric or hydrochloric acid is added. Pink, rouge dissolved in water ; 
—dissolve zaffre 2 oz. in hydrochloric acid 6 oz., filter, add solution of 
carbonate of ammonia in excess, then add 1 fluid oz. of potash solution, 
and dilute with water to produce the required color. Red, cochineal or 
carmine dissolved in water. This, like most of the other colors, is im¬ 
proved by the addition of ammonia. Purple, a little Prussian blue 
added to the red liquid ; sulphate of copper 1 oz., carbonate of ammonia 
1 1-2 oz., water 2 1-2 pints. Violet, ammonio-sulphate of copper dilut¬ 
ed with water, and enough of the pink color mentioned above to produce 
the required tint. Straw-color, gamboge dissolved in water. 

Colored inks. —Dissolve in water any of the usual water colors, par¬ 
ticularly those which are transparent, and add a little gum water to the 
solution. 


CHEMICAL PROCESSES. 


Fis-. 119. 


A 



V 


<'*■ \ 


BC 


AD 



Those processes only which are most important, and which have not 
been already described, can be mentioned. Among these are the follow¬ 
ing :—Method of making filters. Fold 
a piece of thin blotting paper (about 
3 inches square) in half, so as to bring 
the corners C D upon A B, then fold 
the corner B C upon A D, so as to bring 
all the corners together at A. These 
are now all cut off in the dotted line 
E F, and the filter is finished by separ¬ 
ating one of the folds, d, from the 
others, a, b, and c. The filter thus 
made, may be suspended in a funnel, 
or in a glass or porcelain hoop. 

A more convenient method of mak¬ 
ing filters is to cut a number at once 
in a circular form. This is done by 

placing a circular vessel (as a glass jar) over several thicknesses of filter 
paper on a board, and then cutting around the edge of the vessel with 
the point of a knife. The pap^r thus cut out in the form of circles, is 
afterwards folded as directed above. For common filters, ordinary 
printers’ paper will answer. The filter should generally be moistened 
with some of the liquid of the substance to be filtered before the whole 
is poured in. If, for example, the substance is dissolved in water, the 
filter should be previously moistened with water; if alcohol is the sol¬ 
vent, the filter should be moistened with alcohol. When thus moistened 
the filter is less apt to be broken by the fluid which is poured in, and it 
also separates a liquid of a different nature. Thus when water and oil 
are mixed, if the filter is previously moistened with water, the oil is pre¬ 
vented from passing through, and in this way the water and the oil 
may be separated. Washing a filter, or rather the solid substance left 
on the filter, is done by directing a small stream of 
water upon it from the washing bottle (Fig. 120), or 
the dropping tube (Fig. 121.) The latter is held 
under water until it is full. Or, the extremity of it 
may be plunged into water, and the mouth applied 
at the top, when by suction the air will 
be drawn out, and the water will rise till 
the tube is filled. The thumb is then 
placed over the top, and in this way the 
water is retained in the tube until it is 
brought over the filter. The thumb is 
then removed and the water flows out at 
p- the lower end. of the tube. The dropping 

rrice tfu.ou. tube is of constant use in a course of 


Fig. 120. 




121 . 



























350 


ELEMENTS OF CHEMISTRY. 


chemical experiments. To prepare tubes for corks , it is often necessary 
to fuse a narrow rim or edge on the end of the tube. This may be done 
by the blowpipe, and by pressing the end of the tube while red hot 
against a smooth block of wood. This fusion strengthens the end of 
the tube, and prevents its tendency to split apart when a cork is pressed 
into the tube. To bend glass tubes, if the tube is small use the heat of 
a lamp. Heat the tube on all sides till it. begins to fall of itself, then 
withdraw it from the lamp, and bend it with the hands. A better and 
more gradual curve can often be obtained by allowing the tube to fall 
into or take by its own weight while red hot the required form. Large 
tubes should be bent in a charcoal furnace. Glass vessels may be divid¬ 
ed, when required, by means of a stout iron wire or rod, hammered to a 
point. Heat the end of this to redness, and lay it on the glass at a short 
distance from where you wish to divide it. A crack will be produced, 
which may be diverted in any required direction by the heated wire. 
To seal a tube hermetically , heat it red hot in the alcohol lamp or in a 
furnace. It may then be drawn out to a fine point, and by melting the 
point thus formed the tube is perfectly sealed. To blow a glass bulb. 
With an alcohol blast of great power this is easily done. The tube is 
first melted at the end, and drawn out to a point with a small labora¬ 
tory tongs or a pair of pincers. This point is then melted so as to dif¬ 
fuse the glass as much as possible over the end of the tube. It is better 
at first to hold the tube slightly inclined upwards, then horizontally, and 
finally for a short time downwards, turning it all the time. If the lamp 
is of sufficient power, a mass of glass may thus be collected on the end 
of the tube. This is now removed quickly from the lamp and blown 
into a bulb. The blowing should be gentle at first, and should gradually 
increase in force till all the glass is cooled. It is also better to continue 
turning the tube while blowing. The thinnest parts of the glass will 
cool first, and by continuing to blow with increased force the thicker 
parts which remain stiil melted will be expanded and rendered thinner, 
and thus a bulb of uniform thickness obtained. To Jit a tube within a 
cork, a hole the size of the tube is made with brass cork borers , or, 
where these are not to be had, by boring the hole with a red hot iron 
somewhat smaller than the tube to be inserted, and enlarging the hole 
thus made with a red hot glass tube. The red hot glass makes a smooth¬ 
er and a more uniform hole through the cork than iron wire, as it re¬ 
tains heat longer, and is itself a smoother surface. 

Process for making blowpipe beads. The finest platinum wire is se¬ 
lected, and the end bent into a hook (Fig. 122.) 

Fig. 122. This hook should not be larger than the extremity 

----O of au ever-pointed pencil (so that a pencil lead of 

ordinary size will pass through). It is moistened 
and applied, to some pulverized borax, aud the powder thus taken up is 
exposed to the blowpipe flame. The water of crystallisation is thus 
driven off, and the borax melts into a transparent bead. Moisten the 
bead thus formed and apply it to the powder of the substance under 
examination. Again fuse the bead in the blowpipe flame, and the color 
which it acquires will in many cases determine the body uuder examina¬ 
tion. An exceedingly small quantity of the substance must be taken on 
the borax bead, as a larger portion wmuld often render the bead opaque 
and destroy the reaction. Beads with carbonate of soda and several 
other substances may be formed in the same manner as that with borax, 
and are often very useful in detecting the presence of bodies in minute 
quantities. 



EXPERIMENTS. 


351 


Charcoal is much used for blowpipe experiments. That from well- 
grown pine wood, or from the branches of the willow, is to be preferred. 
It should be well charred, and as free as possible from ashes: where¬ 
fore dense and compact woods, containing much ashes, should not be 
used. The assay is placed on a shallow concavity near one end of the 
support. The substance to be examined is reduced-to a fine powder, 
and mixed with soda, or other flux, to a thick paste, by moistening with 
a little water on a slip of glass or ivory. The whole is then to be placed 
on the charcoal, and the blowpipe flame cautiously directed upon it. 
For most purposes very small quantities should be used. 

In testing with liquid reagents it is generally best to dilute the solu¬ 
tion of the substance under examination with distilled water or pure rain 
water. Hence, take in a test-tube (Fig. 129), as much of the substance 
as will fill the convex part of the tube to a, add an equal quantity of 
water, and then drop in the least portion of the reagent which will an¬ 
swer. 

Composition and method of using cement. Resin 5 oz., beeswax 1, 
Spanish brown 1. Melt together and add a teaspoonful of plaster of 
Paris or brick dust. When melted and well mixed, allow the whole to 
cool, till it will not burn the hand when this is wet. Then pour into the 
hands (being wet) a little of the cement, and work it up into a roll or 
stick. It will be found most convenient in this form. These rolls may 
sometimes be made on a wet table, and of various sizes. We have 
found it convenient to have various sizes from an inch thick down to a 
size even smaller than the ordinary size of sealing wax. Surfaces to be 
cemented should be previously heated, to expel the moisture with which 
they are almost always more or less coated. On the surface while heat¬ 
ed rub a little cement, enough to make a coating. This will ensure a 
perfect adhesion between the surface and the cement when melted and 
applied in larger quantity. This is the only sure way of making per¬ 
fectly tight cement joints. Iron cement. —16 oz. of iron filings, 2 muriate 
of ammonia, 1 flowers of sulphur. Mix these well in a mortar and keep 
them in powder, dry. When the cement is wanted for use take one 
part of this mixture with twenty parts of iron filings, grind them together 
in a mortar, mix with water to a proper consistency, and apply the ce¬ 
ment between the joints. This cement is extensively used by iron found¬ 
ers, and is found to be very excellent, as in time it unites with the iron 
to form a solid mass. 

In decanting liquids from one vessel to another, it is often not only 
convenient but essential to prevent any loss of the liquid by running over 
the side of the full vessel. This may be done by holding a tube or a slip 
of glass in contact with the lip or edge of this vessel. The liquid will 
follow down the slip or tube of glass into the vessel below without any 
loss from the above-mentioned cause. Short slips and tubes of glass for 
this and a great variety of purposes, should be kept on hand in a jar or 
wine glass of clear water, by which they may be always ready for use. 
In cases where considerable quantities of liquid are to be decanted, a 
syphon is the best instrument for accomplishing it. 

To prepare cabbage liquor , cut up the leaves of red cabbage into strips, 
and upon these pour boiling water, and allow the liquid to stand until 
cold. When cold, pour off the liquor>and it is ready for use. Infusions 
from other substances sometimes require that the vessel (as a cup) should 
be placed in boiling water, after this is poured upon the vegetable sub¬ 
stance. Lutes are made of various substances, such as white lead, plas¬ 
ter of Paris, potters' clay, &c. Where the article to be heated is to be 


352 


ELEMENTS OF CHEMISTRY. 


exposed to great heat, the best lute is made of potters’ clay (or even 
ordinary clay) 1 part, and white sand 3 parts. In most cases where 
junctions are to be made which are not to be exposed to a jet of steam 
or to watery vapor, potters’ clay is used (see Expt. 20). Where watery 
vapor is to be guarded against, white lead is used. 

In boiling certain liquids the ebullition is often so violent as to endan¬ 
ger the vessel, if this is glass. The danger may, in most cases, be re¬ 
moved by dropping into the liquid some particles of a solid which will 
not be acted on, as small pieces of glass, charcoal, brass wire, <fcc. Small 
coils of platinum wire are best adapted to this purpose, on account of 
the insolubility of platinum in most liquids, and its great weight, which 
causes it to remain below the surface of the boiling liquid. In boiling 
liquids of this kind the vessel should never be more than three fourths 
full. 

The liquid to be evaporated must often be protected from dust and 
other causes of contamination. This is done by covering the evaporat¬ 
ing dish with a piece of filter paper of sufficient size. This is supported 
on three strips of glass which lie across the edges of the evaporating 
dish in the form of a triangle, and is held down by another strip of 
glass which is placed above the whole. A better method is to make a 
double hoop , the inner hoop of wood, and the outer considerably wider 
(an inch and a half) of pasteboard (or also of wood). The pasteboard 
hoop slips over the wooden one, and the edges of the filter paper are 
held between both hoops, so that the paper is stretched across the inner 
hoop like the head of a drum. A single wide hoop will answer, for a 
paper cover will last for a long time, and when it is broken, through, a 
second may be pasted over the whole. 

Among the conveniences of a laboratory, wires of different kinds and 
sizes should always be at hand. Small copper wire (binding wire) is of 
constant service. Wire triangles of different sizes are often useful, par¬ 
ticularly in supporting objects over a furnace or a lamp. A very con¬ 
venient small portable furnace may be made by inverting the wire cover 
of a mouse trap. A few pieces of ignited charcoal thrown into this fur¬ 
nace, produce a far higher and more uniform heat than that of an ordi¬ 
nary, alcohol lamp. Lamp-lighters made of paper are also frequently 
very useful. Important experiments may be rendered unsuccessful for 
want of small facilities of this kind. They may be kept on hand in a jar. 

It is frequently desirable to increase for a short time the heat of an 
alcohol lamp (as in the process of making oxygen gas). This may be 
done by holding a strip of newspaper or any other waste paper in the 
lamp. It will be found very convenient to keep on hand a quantity of 
paper for this purpose. The heat of a lamp, if this has a broad top, 
may sometimes be most conveniently increased by adding with a pair of 
pincers or tongs small pieces of cotton which have been dipped in alco¬ 
hol. A great volume of flame may be in this way produced. No danger 
is incurred if the lamp is a metal one, and the cotton may at any time be 
removed should the heat become too great. 

To save time in cleansing apparatus, it may be well to keep on hand 
a bottle of potash solution, and another to receive strong acid solutions, 
which, containing various impurities from use, are unfit for any other pur¬ 
pose. Flasks may often be cleansed by agitating wet paper, alone or 
mixed with wet sand, within them. Test-tubes may be cleansed by a 
swab made to fit them of a stick covered with lamp wick or strips of 
cotton cloth, or better by teasel attached to an iron wire and fitting the 
test-tube. 


CHEMICAL APPARATUS. 


Fig. 123. 




cl 


JH 


hi. 



y 


Gasometer. The cheapest form of gasometer is represented in Fig. 
123. It consists of a tin or wooden box, to which are attach¬ 
ed a funnel tube, k, made of tin, and extending nearly to the 
bottom of the box, a stopcock, d, and a short tube, b, opening 
into the box near the bottom. This short tube is stopped with 
a cork or a metal cap. The gasometer is filled with water 
by stopping b, and opening d, and also c, which is a stopcock 
in the funnel tube. Water is then poured in at k; by which 
the air is driven out of the gasometer at d, and the gasometer 
filled with water. When full, c and d are shut and b is open¬ 
ed. Little or no water escapes when b is opened, as the wa¬ 
ter within the gasometer is supported by the pressure of the 
atmosphere.* The gas is collected by thrusting the tube from which it 
is delivered through b, entirely within the gasometer. The gas is then 
heard to bubble over, and rises to the top of the gasometer within, while 
an equal bulk of water escapes through b (around the gas tube which is 
not so wide as b, and therefore occupies but a portion of its cavity). 
When the gasometer is full of gas, b is closed and a flexible tube attach¬ 
ed to d; c is then opened, and water poured in at k. This descending 
into the gasometer expels the gas through d, and through the flexible 
tube attached to d, by which it is conveyed where it is desired. The 
contents of the gasometer should be at least a cubic foot. 

The pneumatic cistern is made so as to contain one or more gasome¬ 
ters with other conveniences for collecting or decanting gases. In Fig. 

124 is represented a pneumatic 
cistern with four gasometers. 
Two are placed on each side 
with a wide space, e, filled with 
water between. Water also flows 
over the tops of all the gasome¬ 
ters, these being placed a little 
below the top of the pneumatic 
cistern. These gasometers differ 


Fig. 124. 




Is 

iJnl 




from that represented in the last figure only in having a short tube, c, 
on the side, the stopcock of which may be opened or shut by the wires, 
h and i. These wires extend nearly to the top of the water, and this 
arrangement takes the place of the funnel tube, k , in the last figure. 
When the space, e, is filled with water, b, b, b, b, (the two last belonging 
to the two interior gasometers are not represented) are shut, and the 
four stopcocks on the gasometers (d), as well as the four valves (c), are 
opened. The water then flows in from the space e, into all the gasome¬ 
ters through the valves (c), while the air is driven out through the stop¬ 
cocks (d). When all the gasometers are full of water, they may be 
filled with four different gases, or with the same gas, by stopping the 

* The same principle is applied in the construction of a common form of inkstand. 

























354 


ELEMENTS OF CHEMISTRY. 


valves (c) and the stopcocks ( d ), opening b, b, b, b, and thrusting the tube 
conveying the gas through these short tubes entirely within the gasome¬ 
ter as before. When filled with gas this may be expelled from the gas¬ 
ometers by closing b, b, b, b, opening the valves (c) and the stopcocks ( d ), 
the space, e, being kept full of water. The water now runs in through c, 
and the gas escapes from d. Over the space, e, is seen at g a sliding shelf 
which slides along on the edge of the gasometers. There is an opening 
through this shelf, and a short fupnel attached beneath by which gas may 
be conveyed upwards to ajar filled with water and standing on the shelf. 

The following articles of apparatus have been mentioned in the preced¬ 
ing pages of this work, and are therefore inserted partly for the sake of 
reference: 


Fig. 125. Fig. 126. Fig. 127. Fig. 128. 

Lamp Stand. Stopped Jar. Transfer Jar. 



Fig. 128 represents the arrangement for washing a gas , as hydrogen 
(Expt. 24). The gas is generated in the larger bottle and passed through 
lime water or some other purifier in the smaller bottle. This wash-bot¬ 
tle serves also to retain any liquid or solid matter mechanically carried 
over with the gas. In Fig. 129 are seen a test tube and holder. 
Fig. 129. The holder is formed by folding up a piece of paper into a strip 
about an inch wide and four inches long, and containing four 
or five thicknesses of paper. This strip is wrapped 
about the tube, and held at the two ends. Test-tubes Fig. 130. 
are sold at about 50 cents per dozen, the price depend¬ 
ing upon their size and quality. 

The extremity of the common blowpipe (Fig. 131) 
may be coated with varnished paper to prevent the 
bad taste of the brass tube in the mouth. It is some¬ 
times gilded by the electrotype process for the same reason. 

The Berzelius blowpipe (Fig. 132) 
has a platinum jet, an ivory mouth¬ 
piece, and an ivory reservoir. It 
is made in four pieces with ground 
joints. 

Flexible tubes are either of lead or caout- 
$0.38. chouc. The latter are to be preferred, but 

a lead tube, 2 or 3 yards in length, and provided with a stopcock on one 
end, is often very convenient. Three or four brass stopcocks should be 
obtained, and as many screw connectors. The former are sold at $1.00 


Fig. 131. 

Commou blowpipe. 


o 





































APPARATUS. 


355 


each, the-latter at $0.25. Sheet India Rubber may be obtained for $0.50 
per square foot. Fig. 133 represents the method of making India rub¬ 
ber connectors out of sheet India rubber. A small strip of India rubber 

is wrapped around a tube of the required 
size. The ends of the strip are then cut off 
by a pair of scissors in the 
direction represented by the 
dotted line. The new-cut 
edges unite with each other, 
and their union may be ren¬ 
dered more perfect by pressing them together with the nail (but without 
touching them). The India rubber connector thus formed may be slipped 
off from the tube, and applied to the purpose for which it is to be used. 
Connectors may be had ready made at 15 cts. per dozen, and a few will 
last a long time and serve a great variety of purposes. 

A measuring glass is often required. These glasses vary in size, 
form, and mode of graduation. It is therefore best, if possible, to 
have more than one kind. They vary in price from 60 cents (holding 
one fluid ounce) to $1.50 (holding sixteen ounces). 


Fig. 133. 


Fig. 132. 
Berzelius blowpipe, 



12.50. 











. 


- 

- 




' 

* 






















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POESIE. 


Ancelot (Mme.) 

Desmahis. 

Lebrun. 

Rotron. 

Andrieux. 

Ducis. 

Malherbe. 

Rousseau. 

Arnault. 

Florian. 

Millevoye 

Sainte-Beuve. 

Bcranger. 

Fontanes. 

Moliere. 

Soumet. 

Boileau. 

Gilbert 

Parny. 

Tastu (Mme.) 

Chenier. 

Gresset. 

Piron. 

Valmore (Mme.) 

Corneille. 

Hugo. 

Quinault. 

Viennet 

Cr6billon. 

La Fontaine. 

Racan. 

Yigny (de). 

Dolavigne. 

Lamartine. 

Racine. 

Yoltaire. 

Delille. 

La Bailly. 

Regnard. 



PROSE. 


Aguesseali (u 1 ). 

Cousin. 

Maistre (J. de). 

Saintine. 

Aim6-Martin. 

Cuvier. 

Marmontel. 

Salvandy. 

Arago. 

D’Alembert. 

Mascaron. 

Sand. 

Ballanche. 

Diderot. 

Massillon. 

Saurin. 

Balzac (Guez de). 

Duclos. 

Maury. 

Scribe. 

Balzac (H. de). 

Dumas. 

Mezeray. 

Segur. 

Barante. 

Pension. 

Michaud. 

Sevignd (Mme. de). 

Barthelemy. 

Flechier. 

Michelet. 

Sismondi. 

Beaumarchais. 

Fontenelle. 

Mirabeau. 

Stael (Mme. de). 

B. de St. Pierre. 

Gurnard. 

Moliere. 

Thierry (A.) 

Bonaparte (N.) 

Guizot. 

Montesquieu. 

Thiers. 

Bossuet. 

Hugo. 

Nodier. 

Thomas. 

Bourdaloue. 

La Bruyere. 

Pascal. 

Vauvenargues. 

Bridaine. 

Lac6p&de. 

Raynal. 

Yertot. 

Buffon. 

La Harpe. 

Rollin. 

Vigny (A. de) 

Chamfort. 

Lamartine. 

Rousseau (J. J.) 

Villemain. 

Chateaubriand. 

Lamennais. 

Sainte-Beuve. 

Yolney. 

Cormenin. 

La Rochefocauld. 

Saint-Real. 

Voltaire. 

Courier. 

Mably. 

Saint-Simon. 


A revised and 

improved edition. 

, enriched with Biographical and 


Vritical Notes, and with Selections from Writers of the present time. 

Le Si6ge de la Rochelle, par Mme. de Genlis. 12mo. $1. 

“Wo have read with great pleasure ‘Le Siege de la Rochelle,’ and 
teoommend it as one of the best books for translation there is publish- 
4 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


bd. It is considered one of the most popular of Mme. de Genlis’ works, 
whose name is well known in French literature. The narrative is in¬ 
tensely interesting, and will command attention to the close. Though 
a work of fiction, the incidents are partly founded on fact: the historical 
Beenes and characters are correctly drawn, and present a fair view of 
this most eventful period of French history. 

“Containing none but just and moral sentiments, it is admirably 
adapted to be used as a School Eeader, and we trust that it will meet 
with the favor it deserves.” 

Le Vicaire de Wakefield, par Goldsmith. 12mo. 75 cts. 

In translating ‘this beautiful English Classic into French, special care 
has been taken to preserve the beauty and simplicity of the style ; and 
we trust that the present effort to render it a School Reading Book will 
meet with favor. 

CEuvres Completes de Moli&re. 2 v. 12mo. 1334 pp. $2.00 

This edition contains all the works of this great author, and is beau¬ 
tifully printed, on fine paper. 

CEuvres Choisies de MoliSre : contenant La Bourgeois Gentil- 
homme, Le Misanthrope, et Les Femmes Savantes. 18mo. 63 c. 

The editor has carefully revised the text, and has faithfully followed 
the most approved Paris editions. As to the Comedies selected, though 
many others of the same writer are at least equal, if not superior, in 
merit, it must be remembered that this is a Moliere intended for schools 
and for the use of young persons, and the selection has been made in 
reference to that object. 

CEuvres Completes de J. Racine : contenant, La Thebaide, ou 
Les Fibres ennemis—Alexandre—Andromaque—Les Plaideurs 
—Brittanicus — Berenice — Bajazet — Mitliridate — Iphigenie— 
Phfedre—Esther—Athalie. Edition annotee d’apres Racine fils, 
Madame de Sevigne, Le Batteux, Voltaire, La Harpe, Napoleon, 
Schleyel, Roger, Geoffroi, Patin, Sainte-Beuve, Saint-Marc Gi- 
rardin, Nisard, etc. 12mo. 760 pp. $1. 

AVIS SUR CETTE EDITION. 

Parmi les grands 6crivains qui honorent notre literature, il en est peu 
dont les oeuvres aient ete aussi frequemment reproduces que celles da 
Racine. Les grammairiens, les critiques et les commentateurs litt6raires, 
out depuis deux siecles etudie ses compositions sceniques pour y cher- 
eher les uns des modules de style, les autres le module de Part et du 



BOOKS PUBLISHED B? ROE LOCKWOOD & SOIL 


goftt, et les nombreux travaux dont ce poete a jamais celebre a 6td 
l’objet, nous imposaieiit de grandes obligations; aussi nous sommes- 
nous efforce de rendre irreprochable l’edition que nous publions au 
jourd’hui. 

Nous avons donne d’abord toutes les prefeces, parce qu’elles forment 
T indispensable introduction des pieces; qu’elles en contiennent sou- 
vent 1’analyse et l’examen, et que Eacine y developpe avec la superiority 
de son genie ses theories esthetiques. 

Nous avons aussi reproduit toutes les variantes, parce qu’on voit la 
les premiers essais du poete, le travail de son gout dans le choix des 
mots, et son constant effort pour approcher autant que possible de la 
perfection. * * * Comme toujours, nous avons fait predominer le 
commentaire moral et psychologique, et en rapportant a l’oecasion le 
jugement des contemporains du poete, a partir du grand Conde et de 
madame de Sevigne, nous avons suivi, en ce qu’ils ont de plus saillant, 
les travaux des critiques et des historiens litteraires, depuis Eacine fils, 
jusqu’a messieurs Sainte-Beuve, Nisard et Saint-Marc Girardin. On a 
de la sorte, dans le blame et dans l’eloge, l’echo fiddle de l’opinion dans 
un espace de pres de deux siecles. 

Ainsi, notre Edition offre, jusque dans les moindres variantes et les 
moindres fragments, tout ce que Eacine a ecrit pour le theatre, et sous 
une forme concise tout ce que l’histoire litteraire a dit de plus essentiel 
sur ce theatre lui-m6me. 

CEuvres Choisies de Jean Racine: contenant Bajazet, Andro- 
maque, Iphigenie et Esther. 18mo. 63 cts. 

it has long been desirable that the works of this great poet should be 
uBed in our schools as a reading-book; but as his writings are too 
voluminous for that purpose, a proper selection of his best pieces has 
been made. This selection the editor trusts will prove acceptable to all 
instructors and professors of the French language, as well as to all 
interested in French literature. 

It is printed with great accuracy, thus removing the usual objection 
to the editions of French works published in this country. 

De l’Allemagne, par Mme. De Stael. 12mo. 638 pp. $1. 

This has been considered the most popular of Mme. De StaePs 
works, and has always sustained a high literary reputation. 

Presenting an interesting and truthful Description of Germany—the 
Manners and Customs of the Germans—their Literature, Arts, and 
Sciences—Views of Philosophy, Morals, and Eeligion—and thus com¬ 
bining instruction with the study of the language, it is pre-eminently 
adapted for an advanced class-book. 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


Aventures de Gil Bias de Santillane, par Le Sage 
12mo. $1. 

It has for some time been a matter of doubt whether the “Adventure* 
0 / Gil Bias ” was the work of a Spanish or French writer; but we be¬ 
lieve it is now generally conceded to be the production of the latter. 

Although not free from objections for indiscriminate use, yet it has 
always been considered a desirable book for translation, from the fact 
that, consisting as it does of a series of narratives abounding in collo¬ 
quial expressions, and being connected very indirectly, the reader is 
not wearied as he would be by a lengthy story, the interest continuing 
as the scene changes. 

Fables de La Fontaine. 100 engravings. 18mo. 63 cts. 

La Fontaine’s beautiful Fables are known to every French scholar, 
and are admirably adapted to be used as a book for translation. 

Each fable is followed by its appropriate moral; and thus just prin¬ 
ciples, in a pleasing manner, are inculcated into the mind of the reader 
while engaged in his study. 

Atala, Rene, par Chateaubriand. 12mo. 60 cts. 

The beauty of Chateaubriand’s writings has established for him a 
high literary reputation. 

This little work has always been considered the most popular of his 
minor productions, and was originally a part of the “ Genie du Christia- 
nisme,” although latterly it has been generally published in a separate 
form. 

It was written, as the author says, “in the wilds of America, and 
under the tents of the savages,” and the incident on which the story 
is founded is mentioned in his “ Voyages en Amerique.” 

It is printed from the author’s last edition, and in a large clear type, 
and the Publishers hope that it will meet with favor as a Reading 
Book for school use. 

Paul et Virginie, par Bernardin de Saint-Pierre. 60 cts. 

“ This most delightful work is too favorably known to require any 
recommendation from us. The beauty and simplicity of the style, to¬ 
gether with the interest of the story, have always rendered it a favorite 
With young persons. We trust that the present edition, intended for 
schools, will meet with general acceptance.” 

The same work, with a Full and Correct Vocabulary of all the 
Words and Idiomatic Expressions contained in the book; also 
Interlinear Translations, both free and literal, of the first few 
pages, with the Pronunciation of the French indicated by 
English sounds. 12mo. 62 ota 

T 



BOOKS PUBLISHED BY ROE LOCKWOOD <fc SON. 


Elisabeth, ou Les Exil6s de Sib6rie, par Mme. Cottin. 

12mo. 60 cts. 

“The incident which gave rise to this history is founded in truth. 
No imagination, however fertile, could produce actions so heroic, o? 
sentiments so noble and elevated. The heart alone could inspire them. 
* * * Authors have frequently been accused of representing the 
beauties of virtue with too bold a pencil and in colors too vivid. Far 
am I, however, from presuming to insinuate that this criticism is ap¬ 
plicable to myself, who possess not the abilities requisite to attain this 
brilliant though creative talent; nor do I conceive that it is in the 
power of the most eloquent author, by all the studied embellishments 
and decorations of language, to add a single charm to the innate beau¬ 
ties of virtue. On the contrary, she is in herself so far superior to the 
adscititious aids of ornament, that it would rather appear impossible 
to describe her in all her native dignity and loveliness. This is the 
chief difficulty I have experienced in writing Elisabeth.” —Translation 
of extract from Author's 'preface . 

The same work, with a Full and Correct Yocabulary of all the 
Words and Idiomatic Expressions contained in the book; also 
Interlinear Translations, both free and literal, of the first few 
pages, with the Pronunciation of the French indicated by 
English sounds. 12mo. 63 cts. 


Conversational Phrases Classified, or French Synonimes, 
by J. L. Mabire. 16mo. 46 cts. 


Most of the Guides to French Conversation heretofore published in 
this country have been merely collections of certain conversations on 
specified subjects, which, unless they were again to recur in the precise 
form of the lesson, would be of but little assistance to the student. In 
other words, he but stores his mind with set formal phrases for specific 
occasions, without an acquaintance with the genius and power of the 
language, or the ability to adapt his knowledge to the peculiar and va¬ 
ried circumstances of every-day life. » 

This work is arranged on an entirely new plan. It consists of the 
most familiar phrases of every-day conversation, classified according to 
their sense under various appropriate heads, such as the following: 


1. To tire, weary, grow tired. 

2. To affirm, assure, warrant, attest. 

8. To obey, yield, submit. 

4. To imagine, believe, persuade one’s self. 

5. To admire, astonish, surprise. 

6. To depart, set out, travel, ride. 

7. To light, kindle, blow, extinguish. 

8. To warm, cool, dry, wo*. 

9. To laugh, smile, weep, joke. 

10. To dance, salute, greet, bow. 


11. To design, draw, sketch, paint. 

12. To pray, beseech, ask, entreat. 

13. To approve, consent, permit, tolerate 

14. To lodge, live, dwell, remove. 

15. To raise, lift, open, shut. 

16. To rail, slander, insult, injure. 

17. To commend, praise, flatter, compliment. 

18. To blame, reprimand, criticise. 

19. To place, put, set, lay, arrange. 

20. To contemn, despise, depreciate, disdain. 


With an Alphabetical Index. 


8 




BOOKS PUBLISHED US' ROE LOCKWOOD it SON. 


It is divided into 236 similar heads, besides containing Models of 
Notes, Invitations, Letters, the most Difficult and Common English 
Idioms,-&c. 

It has acquired an extraordinary popularity in England, having, in 
a few years passed through many editions, numbering over 100,000 copies. 

Le Livre des Petits Enfants, avec Vocabulaire. 50 cts. 

This little volume of Easy Tales was published in France for the use 
of Young Children who had just learned to read. The design of the 
authoress was, by a series of entertaining narratives, to allure the 
Young onward in the path of learning, and at the same time to imbue 
their minds with sentiments of religion and virtue, and of love for che 
Sacred Scriptures. 

To the carefully printed text is added a literal English translation of 
the first ten stories, and a full vocabulary to the remaining ones. 

These facilities, together with the simple style of the stories them* 
selves, render this book one of the easiest for translation. 

Mrs. Barbauld’s Lessons for Children, in French, with 
a Vocabulary. 16mo. 45 cts. 

To attempt a eulogy of “Mrs. Barbauld’s Lessons for Children” 
would be superfluous. We only remark that, on account of its extreme 
simplicity, no book is better suited for young persons commencing the 
study oT French. 

It is translated with great care, and is beautifully printed on a large 
clear type, with illustrations. 

“ The task is humble, but not mean; for to lay the first stone of a 
noble building, and to plant the first idea of a beautiful language in a 
human - mind, can be no dishonor to any hand.”— Mrs. Preface. 

First Lessons in Learning French, by Prof. Gustave 
Chouquet. 16mo. 45 cts. 

This work is intended for pupils commencing the study of the French 
language. In such a work it is not necessary that the rules of grammar 
should be formally introduced; they serve rather to weary and embar¬ 
rass than to profit. 

In design and execution it is so simple as to be within the reach of 
any child, however young, who is capable of reading in English. The 
present edition is much enlarged and improved, and printed on very 
large type. It is divided into six parts, as follows, viz.: 

Part I. Spelling Lessons, designed also for Exercises in Pronunciation. 

Part IT. Simple and Progressive Lessons in Grammar and Translation. 

9 



BOOKS PUBLISHED BY ROE LOCKWOOD <fe SON, 


Pabt III. A Vocabulary of the most Common and Familiar Obje <4, 
together with appropriate Exercises in Phrases and Short Sen¬ 
tences ; the whole divided into lessons, each embracing a Ins¬ 
tinct Subject. 

Part IV. Examples of French Verbs, auxiliary, regular and reflec¬ 
tive, fully conjugated. 

Part V. A few simple Stories, the first few followed by a Translation 
of the more difficult Words and Idioms. 

Part VI. A collection of simple and familiar Conversational Phrases, 
divided into short and easy lessons. 

French Spelling and Pronunciation, by H. Vannier. 45 cts. 

After a careful examination of the most recent and approved ele¬ 
mentary Spelling-Books published in France, we have selected the 
system ofH. Vannier, asbeing the simplest and yet the most methodical. 

It is divided as follows: 

Part I. Exercises on all the Sounds and possible Combinations of 
Articulations and Words. 

Part II. Spelling Lessons, or a Vocabulary of the most useful Nouns 
in the French Language, systematically arranged under distinct 
heads. 

Part III. Examples of French Verbs—auxiliary, regular, and reflect 
ive—fully conjugated. 


SPANISH. 

Del Mar’s Guide to Spanish and English Conversation, 

containing various lists of Words in most general use, properly 
classified ; collections of Complimentary Dialogues and Conver¬ 
sational Phrases on the most general subjects of life ; Proverbs 
and Idioms; also comparative Tables of Coins, Weights, and 
Measures. 12mo. 75 cts. 

In this new edition the Proverbs and Idioms, as well as the Dialogues, 
have been considerably enlarged; the New Orthography has been in¬ 
troduced, according to the last decision of the Spanish Koyal Academy; 
and a Treatise on Spanish Pronunciation has been prefixed. 

These additions will further advance the utility of the work, and rea¬ 
der it still more worthy of public favor. 

10 





BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


Vingut’s Ollendorff’s Spanish Grammar : a New Method ol 
Learning to Read, Write, and Speak the Spanish Language: 
with a Figured Pronunciation of the Spanish Words. To 
which is added an Appendix, containing a full explanation of the 
Alphabet, with Exercises in Spelling; a Summary of the Rules 
given in this Method, with a Treatise on the Verbs ; a Series of 
Letters for a Mercantile Correspondence, with a Key ; a New 
Spanish Reader and Translator, being a new method of learning 
to translate from Spanish into English, and from English into 
Spanish, containing Extracts from the most approved works, 
Colloquial Phrases and Words in general use; the whole ar¬ 
ranged in progressive order, with especial reference to those 
who study by Ollendorff’s Method. 12mo. $1.50. 

Key to Vingut’s Ollendorff’s Spanish Grammar. 75 cts. 


FOR SPANIARDS LEARNING ENGLISH. 

Vingut’s Ollendorff—El Maestro de Ingles, metodo practico 
para aprender a leer, escribir y hablar la Lengua Inglesa segun 
el sistema cfe Ollendorff, dandose una Demonstracion practica 
del modo de escribir y pronunciar cada una de las palabras 
contenidas en las lecciones y uu Apendice que contiene los Ele- 
mentos de la Lengua Inglesa, tornados de la ultima edicion ds 
Urcullu, publicada en Cadiz en 1845, habiendose correjido y 
aumentado considerablemente ; comprendiendo toda la parte 
elemental no refundida en las lecciones precedentes; tambien 
un Tratado sobre la Pronunciacion y otro sobre la Propiedad de 
las Voces, que bajo un mismo significado en espanol tienen dos 6 
mas en ingles, con diferente uso 6 sentido; 6 al contrario, con 
un solo significado en ingles y dos 6 mas en espanol; compren¬ 
diendo un Lector y Traductor Ingles, 6 sea Nuevo Metodo para 
aprender a traducir del ingl5s el espanol y viseversa, el cual 
contiene un Guia de la Pronunciacion inglesa, y Direcciones para 
usar los diccionarios de Pronunciacion; una serie de Cartas para 




BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


una correspondencia mercantil, y algunos trozos escojidos para 
Lectura y Traduccion. 12ma $2. 

translation): Vingut’s Ollendorff—The English Teacher, or Ollen¬ 
dorff's New Method of Learning to Read, Write, and Speak the 
English Language, with a Figured Pronunciation of the English 
Words in the Lessons ; to which is added an Appendix, containing 
the Elements of the English Language, taken from the last edition 
of Urcullu's Grammar, published in Cadiz in 1845, revised and 
enlarged; also a Treatise on the Pronunciation and various Sig¬ 
nifications of English Words ; also a new Reader and Translator, 
being a New Method of Learning to Translate from English into 
Spanish and from Spanish into English ; a new Guide to Con¬ 
versation ; a series of Letters for Mercantile Correspondence, 
&c., <kc. 

Clave de los Ejercicios del Maestro del Ingles. 12mo. $1. 

(translation) : Key to the Exercises of “ Vingut’s Ollendorff’s English 
Teacher.” 

Urcullu. — Nueva Gramatica inglesa redueida a veinte y siete 
lecciones, por Don Jose de Urcullu; edicion reimpresa por pri- 
mera vez en America, de la Ultima edicion de Cadiz, considerable- 
mente aumentada y correjida, con una Clave de los Temas; un 
Tratado alfabetico de la Propiedad de las Voces, en que se 
esplica la propiedad de las Voces castillanas que tienen en ingles 
dos 6 mas significados con diferente uso 6 sentido, de lo cual 
pudieran orijinarse equivocaciones, asf en la locucion como en la 
traduccion; un Lector y Traductor ingles, 6 sea Nuevo Metodo 
para aprender a traducir del ingles al espanol y viseversa, el 
cual contiene un Guia de la Pronunciacion inglesa, una serie de 
Cartas para una Correspondencia mercantil, y algunos trozoa 
escojidos para lectura y traduccion. 12mo. $1.50. 

(Prologo de TJrcullu de la Edicion de Cadiz.) 

ALGUNAS PALABRAS SOBRE ESTA NUEVA EDICION. 

La buena acojida que ha tenido mi gramatica en los veinte anos que 
nan pasado desde que la di 4 luz, cuando estuve emigrado en Londres, 
me ha movido a publicar una nueva edicion de la misma. En la pri- 
mera dividj la gram&tica en XXII lecciones. Muchas de las edic'ionea 

12 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


que se han hecho tanto en aquella capital como en otros paises desde 
1825 hasta ahora, hail sido copias de la primera. 

En 1840, estando yo en Oporto, se imprimio alii una edieion en XXV 
lecciones, en la cual hice alteraciones de bastante consideracion; pero 
pocos son los ejemplares qne ban penetrado en Espana. Por con- 
siguiente para satisfacer los deseos de muchos profesores de la lengua 
inglesa, era necesario que se imprimiese en Espana mi gramatica; mas 
no como se ba becbo &ntes de abora en Barcelona, sin mi intervencion, 
V copiando los defectos de la qne se publico en Londres. 

La presente edieion, dividida en. XXVII lecciones, es superior & 
cuantas se han publicado hasta este dia, no solamente por las correc- 
ciones que se ban becbo, como por las materias que se ban aumentado. 
Esplicare esto brevemente. 

Cada una de las lecciones XIV, XV, XVIII y XXII se ban subdivi- 
dido en dos, para que el discipulo pueda aprenderlas mas facilmente 
siendo mas cortas. He suprimido las lecciones XXIV y XXV, porque 
lo que ellas contenian no pertenecia, estrictamente bablando, a la parto 
gramatical; pero el discipulo lo hallara, con notable aumento al fin del 
libro en la lista alfabetica de las particulas inglesas. 

En los modelos de traduccion, be introducido algunas maximas de 
buenos autores ingleses. 

Las poesias inglesas que puse en la edieion heeba en Oporto, ban sido 
traducidas por mi al Castellano. El Herald ode Madrid publied una 
de ellas el ano pasado, y un periddico de Cadiz la otra este ano. He 
aumentado una poesia inglesa, no como modelo, sino para que el dis¬ 
cipulo se ejercite en la traduccion de los numerosos verbos que ella 
contiene. 

La parte tercera de la obra, que no tienen las ediciones anteriores, se 
compone : 1°. de una lista alfabetica de las principales particulas ingle¬ 
sas y su uso en dieba lengua, que &ntes formaba el asunto de las dos 
ultimas lecciones, como ya se ha mencionado. 2°. De una esplicacion 
de muebas palabras y abreviaturas latinas muy usadas en los periodicos 
ingleses, y algunas vozes francesas,. que forman parte de la lengua in¬ 
glesa. 3°. De varios documentOs de comercio utiles para los que pien- 
sen cledicarse a la carrera mercantil. 4°. Finalmente, de una lista de 
abreviaturas inglesas, que tambien puedo asegurar es la mas completa 
que basta abora se ba publicado en Espana. Lo primero y cuarto ba 
’•ecibido un aumento considerable; lo segundo y tercero es enteramente 
nuevo. 

En la parte gramatical be becbo correcciones y alteraciones que solo 
pueden notarse cotejando esta edieion con otras anteriores. 

Si el publico ha recibido antes de ahora favorablemente mi gramatica, 
debo suponer sin ninguna clase de presuncion que todavia ba de mere- 
jer mas su aprobacion la que boy le ofrezco ; y que ya no se podra decii 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


eon razon en lo adelante que era necesario valerse de gramaticas escriliui 
en francos para aprender la lengua inglesa. 

Es muy probable que esta sea la ultima edicion que yo publique, y 
mas si, como presumo, los lazos de familia me obligan a dejar la liermosa 
Espana para establecerme nuevamente en el reino vecino, que por la 
larga serie de anos que en el ke pasado y por los vinoulos que a el m» 
unen considero como a una segunda patria. 

ADYERTENCIA. 

A1 reimprimir por primera vez en America la ultima edicion de la 
nueva Gramatica de Don Jose de Urcullu, pubkcada en Cadiz por el 
inismo autor con las considerables mejoras que esplica en su Prologo, 
hemos kecko todo lo que ka estado a nuestro alcance paia mejorar la 
obra, lo que creemos kaber conseguido por los medios siguientes: 

1°. Arreglando la conjugacion de los verbos, segun las mejorea 
gramaticas inglesas, anadiendole por consiguiente el modo Potencial, 
desconocido en nuestra conjugacion, por cuya razon la mayor parte de 
los gramaticos lo kan confundido con nuestro Subjuntivo, que es a todas 
luces distinto en su uso y aplicacion, despojando asi a la conjugacion 
inglesa de la inmensa ventaja que en precision y enerjla le dan sus 
auxiliares. ' 

2°. Ampliando la leccion sobre los verbos auxiliares, la del uso del 
futuro, la del subjuntivo y la de las preposiciones, y redactando entera 
la del imperativo. 

3°. Anadiendo las notas que se kan estimado necesarias, y aun refu 
tando las opiniones del autor cuando se kan creido erradas. 

4°. Dando reglas para la division de las silabas. 

5°. Enriqueciendo la ksta de las abreviaturas inglesas, 4 igualmente 
la de las eliciones. 

6°. Anadiendo un Tratado' de la Propiedad de aquellas voces que, 
teniendo en espanol varias acepciones, se espresa en ingles cada acep- 
cion, con diferente palabra. 

7°. Agregando un Lector y Traductor ingles bajo un plan entera- 
mente nuevo, concluyendo con una serie de cartas parallevar una cor- 
respondencia mercantil, 

8°. Pinalmente, publicando una Clave de los Temas que se kallara, 
al fin de la obra, para que el discipulo compare con ella la traduccion 
que k&gs de los que se dan en la Gramatica. La ventaja de este Clave, 
aun para los que estudien con maestro, es demasiado obvia para que 
nos detengamos en recomendarla. 

Si a todas las mejoras mencionadas se anaden las keckas por el mismo 
autor, segun lo esplica en el Prologo siguiente, facil sera penetrarso de 
las inmensas mejoras de esta edicion sobre todas las anteriores. 

Unwtrsidad de Nueva York, Agosto de 1852. 

14 


E. j. vingut 



BOOKS PUBLISHED BY ROE LOCKWOOD A SON. 


Robertson. Nuevo Curso practico, analitico, teorico y sintetico de 
Idioma Ingles; escrito para los Franceses por T. Robertson; 
obra aprobada por la Universidad de Paris; traducida y 
adaptada al Castellano sobre la ultima edicion del original por 
Pedro Jose Rojas. 8vo. $3.00. 

“La Academia Real de Buenos Letras de la Isla de Puerto Rico, 
despues de baber oido & su Comision de Instruccion publica acerca del 
Nuevo Curso de Ingles por Robertson, adaptado al Castellano por Don 
P. J. Rojas, y considerando que dicba obra reune a su claridad, precision 
y correcto lenguage, una gran facilidad para la adquisicion del idioma 
ingles, y un metodo admirable para la pronunciacion de las palabras, 
ha ordenado que dicha obra se tenga por unico texto en las escuelas y 
colegios, de la Isla.—Puerto Rico, febrero 10 de 1852.—El Capitan 
General, Pezuela.” 

“La Direccion General de Estudios de la Republica de Venezuela, 
habiendo examinado cuidadosamente el Nuevo Curso de Ingles por 
Robertson, adaptado al Castellano por el Senor P. J. Rojas, y consider- 
andolo sumamente util y eficaz para la ensenanza de aquel idioma, ha 
acordado se incluya dicha obra en el catalogo de textos para los Colegios 
y escuelas nacionales.—Caracas 4 de Junio de 1851.—Por la Direccion, 
J. Vargas, Presidente.” 

(■translation) : Robertsonian System; a New Practical, Analytical, 
Theoretical, and Synthetical Course of the English Language, 
written originally for the French, and approved by the University 
of Paris. Translated, and Adapted to the Spanish Language, 
by Pedro Jose Rojas. 

The Royal Academy of the Island of Porto Rico, after hearing tie Com¬ 
mittee of Public Instruction m regard to the New Course of the English 
Language by Robertson, translated into Spanish by Mr. P. J. Rojas, and 
considering that said work combines with clearness, precision, and a correct 
style, a great and wonderful facility for acquiring so difficult a language 
as the English, and that it contains likewise an admirable method of English 
pronunciation, has in its last session ordered this work to be used as the only 
English text-book in aU the schools of the Island.—Porto Rico, February 10th, 
1851.— J. de la Pezuela, Captain General 

“ The General Direction of Studies in the Republic of Venezuela, having 
carefully examined the New Course of the English Language, published in 
France, by Robertson , and translated into Spanish by P. J. Rojas, Esq., 
and considering it highly useful and efficient in teaching that language, hat 
ordered it to be adopted as a text-book in all the National Schools.—Caracas, 
Jane 4 th, 1852 .—By the Direction, J. Vargas, Presidents 


15 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


Emanuel del Mar. Guia para la Conversacion en espanol 

6 ingles, que contiene varias listas de las Yoces mas usuales, 
debidamente classificadas; Colecciones d,e Didlogos de Etiqueta 
y Frases de Conversacion sobre los asuntos mas generales de la 
vida; Refranes y modos de decir; y Tablas comparativas y Mo- 
nedas, Pesos, y Medidas. 12mo. 75 cts. 

Nueva Edicion, cuidadosamente revisada y perfeccionada, y aumen- 
tada con mucbas cosas utiles que ha juzgado podrian ensalzar la utilidad 
de la obra, y hacerla todavia mas digna de la aceptacion publica. 

Los proverbios, Refranes, y Modos de Decio, como tambien los 
Dialogos, han sido considerablemente extendidos, por razon de su 
mucha utilidad al estudiante, tanto en la conversacion como en la lec- 
tura, y se ha tenido cuidado en reunir los que fuesen de uso mas con- 
tinuo en ambos idiomas. 

A esta edicion tambien se le ha agregado un Tratado de Pronuncia- 
oion Inglesa, etc. 

(translation) : Del Mar’s Guide to Spanish and English Conversation, 
containing various lists of Words in most general use, properly 
classified; collections of Complimentary Dialogues and Conver¬ 
sational Phrases on the most general subjects of life; Proverbs 
and Idioms; also comparative Tables of Coins, Weights, and 
Measures. 12 mo. 75 cts. 

New edition, carefully revised, improved , and enlarged by many useful 
additions , which might further advance the utility of the work and render 
it still more worthy of public frnor. 

The Proverbs and Idioms, as well as the Dialogues, have been consider¬ 
ably enlarged, on account of their great use to the student, both in conversa- 
tion and in reading; and particular care has been taken in selecting those 
idiomatic expressions which are most common to both languages. 

To this edition has been appended a Treatise on English Pronunciation. 

16 



BOOKS PUBLISHED BY ROE LOCKWOOD & SON. 


ENGLISH. 


The following Books, by Miss Eliza Bobbins, are intended not merely 
to teach reading for reading’s sake, but to suggest an intelligent method 
of instruction, in preference to one merely mechanical. 

Introduction to American Popular Lessons. 1 v. 18mo. 25 cts. 
American Popular Lessons. 1 y. l8mo. 81 cts. 


Sequel to Popular Lessons. 


1 v. 18mo. 50 cts. 


Primary Dictionary. 1 y. 18mo. 31 cts. 

The following notice, voluntarily presented by the Principals of the 
Public Schools in the city of New York, is but a specimen of many 
others which have been received:— 

“The subscribers, being well acquainted with the series of School 
Books prepared by Miss Bobbins, are desirous to bring their merits 
before those interested in popular education. 

“Proceeding gradually through a complete course of school tuition, 
these works are replete with useful information, and are well adapted 
to improve the moral and mental powers of youth. They bear the 
impress of a mind thoroughly versed in practical education, knowing 
the matter which is suitable, and the manner in which it is to be applied 
to the minds under cultivation. These books have obtained a wide 
circulation, and the approbation with which they are regarded is com¬ 
mensurate to the use made of them. 

“We (the undersigned) hope that such as are interested in selecting 
books for the use of schools will examine this series, the author of which 
has devoted her life to this object.” 


R. S. Jacobson, Public School, No. 1. 


Wm. Belden, do. do. 2. 

David Patterson, do. do. 3. 

John Patterson, do. do. 4. 

Joseph McKeen, do. do. 5. 

J. W. Ketohum, do. do. 7. 

O. S. Pell, do. do. 8, 


Nathan W. Starr, Public School, No. 10. 

Wm. H. Browne, 

do. 

do. 11. 

Asa Smith, 

do. 

do. 12. 

Andrew Stout, 

do. 

do. 13. 

Leonard Hazeltine, 

do. 

do. 14. 

W. A. Walker, 

do. 

do. 15. 

N. Yan Kleek, 

do. 

do. 16. 


“ The Elementary Beading Books prepared by Miss Bobbins, have been 
in use by the Public Schools of this city for many years. I have thor¬ 
oughly examined them, and tested them in practice, and am of opinion 
that they are the best of their kind for the purposes of moral and 
mental development. The selections in them are from the best writers 
for juvenile readers, and judiciously adapted to American Schools, 
wherever the subjects may have required alterations. Her continued 




BOOKS PUBLISHED BY ROE LOCKWOOD <fc SON. 


course of School Books are worthy the highest commendation; and, 
from her matured experience, I have the fullest confidence in Miss 
Bobbins as a writer of School Books. Her Introduction and Popular 
Lessons are unequalled for the purpose of analytical instruction. 

S. W. Seton.” 

“I have been acquainted with the Popular Lesson Series some time, 
and have given them my official recommendation for use in the Schools 
of this State. Ira Mayhew, 

Superintendent of Public Instruction, Michigan.” 

11 1 am well acquainted with the text-books prepared by Miss Bobbins, 
and think highly of their merits. What these merits are, in my opinion, 
I will briefly state. 

They are well written in point of style, showing an acquaintance with 
the best models of English composition, and free from those inaccuracies 
and that carelessness which deface so many of our school books. 

They are well adapted to the comprehension of the several classes of 
children for which they are designed. Nothing is offered to the under¬ 
standing of a child, until it is prepared for its reception. 

They convey a great amount of useful knowledge; and are also emi¬ 
nently suggestive in their character. They fill the mind of a child with 
a healthy love of knowledge, and that lively desire of progress, which it 
is a great end of education to awaken and preserve. 

The moral tone of these books is excellent. They inculcate generous 
sentiments, and appeal to the highest motives. They direct the admi¬ 
ration of children to those qualities in humanity which are most admi¬ 
rable. They thus afford great aid to the teacher, in the moral training of 
his pupils. Geo. S. Hillard.” 

“I have seen Miss Bobbins’ School Books, and some of them I have 
examined with care. They seem to me to have very great merit. They 
are written with good taste, and evince a careful and skilful use of ex¬ 
tensive reading. They are well adapted to excite the mind to inquiry, 
and to fill it with useful and interesting knowledge. 

Their moral tone is excellent; on this score they are wholly free from 
objection. 

The Committee on Books used in our Public schools (of which I am 
chairman) have just resolved, by unanimous vote, to recommend the 
introduction of the Sequel to Popular Lessons ; and others of her 
books are under favorable consideration. 

Boston, July 25, 1846. 


Theophiltjs Parsons.” 



BOOKS PUBLISHED BY ROE LOCKWOOD SON. 


First Lessons in Human Physiology, for the use of Schools, 
to which are added brief Rules of Health: by John H. Griscom, 
M. D., with 50 large and distinct illustrations. 16mo. 42 cts. 

“ This work is written with much care by one fully competent, not only 
in respect of his thorough acquaintance with the subject, but of the 
faculty or tact necessary to secure the attention, by reaching and inter¬ 
esting the minds of children. 

It is strictly a First booh in the study of Human Physiology—a study 
which in importance is second to none, and superior to most of the sub¬ 
jects which are now taught in our schools. 

I am so well acquainted with Dr. Griscom’s writings, and with the 
very sound and practical views he always advances, that I should have 
no hesitation in commending almost any thing from his pen. 

Hon. Horace Mann.” 

Extract from the Minutes of the Executive Committee of the N ew 
York Public School Society, March 4, 1847. 

“ Resolved, That Griscom’s small work on Physiology be adopted for 
general use in the Upper Schools, and that a copy be placed in the 
Primary Schools for each of the Teachers, Assistants, and Monitors.” 

“Dr. Griscom’s First Lessons in Human Physiology, I consider ad¬ 
mirably adapted to the capacity of children, combining in a very happy 
manner, interest and instruction. I shall most cheerfully recommend 
its use in all our Primary Schools. Ira Mathew, 

Superintendent of Public Instruction, Michigan.” 

« Griscom’s Physiology, I consider a work of rare merit; one which 
ought to be in the possession of every child in the land, giving, as it 
does, in a condensed but simple form, much valuable information.” 

Mills’ Blair’s Rhetoric. Lectures on Rhetoric and Belles- 
lettres, chiefly from the Lectures of Dr. Hugh Blair; to which 
are added Copious Questions and an Analysis of each Lecture. 
By Abraham Mills, A. M. Hew and enlarged edition. 12mo. $1. 

{Extractfrom the New Preface.') 

“In presenting to the public an improved edition of the following 
lectures, the editor has endeavored to render the work as nearly com¬ 
plete as the nature of the subject would permit. With this view, he 
has extended the critical portion down to the present period, embracing 



BOOKS PUBLISHED BY ROE LOCKWOOD <fc SON. 


all those writers in English literature who have adorned the language 
with their productions during the last half century. The criticisms, 
though brief, are as extensive as the nature of the work requires, and 
are written with direct reference to the purposes of instruction,” etc, 

Baldwin’s Table Book. A Table Book and Primary Arithmetic, 
compiled and arranged for the Introductory Department of the 
New York Public and Ward Schools, and particularly adapted 
to the system of Mutual Instruction. By Austin Baldwin. 
New edition, revised. 18mo. 10 cts. 

Preface .—Having for a long time sustained considerable inconveni¬ 
ence from the want of a book of Arithmetical Tables adapted to the 
capacities of very young pupils, and arranged in such a manner as to 
answer the purposes of a large school, I have been induced to compile 
one, with a special view to the necessities of the system of monitorial 
instruction. 

Believing it important that children should be made to understand 
the application of what they are required to commit to memory, I have 
placed a few simple questions at the end of each lesson, illustrating its 
use; and as a knowledge of the rules of Arithmetic can be well under¬ 
stood by children, only by performing the operations, I have endeavored, 
in the introduction, to make the rules as concise as possible, depending 
principally on the examples for fixing them in the minds of the pupils. 
It is confidently hoped that this little work will lighten the labor of the 
child in committing to memory that which is so important as a founda¬ 
tion for Arithmetic, and also that, by the division and numbering of 
the lessons, it may relieve the teacher of much trouble in assigning the 
proper portions for each scholar or class. 

That it may, however small the offering, aid the cause of juvenile ed- 


THE COMPILES. 


ncation, is the earnest wish of 


Clarke’s Elements of Astronomy ; a new system of Astronomy, 
in Question and Answer, for the use of Schools. l‘2mo. 21 cts. 

Mrs. Tuthill’s Simple Facts, which every child should know. 


12mo. 45 cts. 


Science of Common Things. 
School Diary, per dozen, 


18mo. 34 cts. 


63 cents 


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